LineageOS + microG here, on a motoX4. It's been the phone I use every day for about a year. My wife has the exact same setup, and generally gets along fine with it. FDroid has _most_ of the stuff we want. Some apps just aren't available there, so we end up using the Aurora store for those, with Warden used to scan those apps and stub out as much tracking code as it can. It's all about compromises, especially for others.
Self-hosted NextCloud replaced Drive/Dropbox, and with some plugins it also does phone/location tracking, secure messaging and video calls, TODO lists, and some more. Self-hosted PhotoPrism replaces Google Photos.
The phone experience hasn't been bad. One thing that came up initially is that most of the open source apps aren't as "pretty", and the UX just isn't as good. I don't care about it too much, and I'm fine with overall using the phone less anyway. The issue that comes up on a regular basis is the Google Maps replacement. OSMand is a great app, but like someone else mentioned it's more of a "look up the address and type it in" experience than a "show me all Thai restaurants in the area" experience. IMO small price to pay, I've been using GPS much less, and I've gotten much better at navigating with my "mental map".
I've used LineageOS without Google services for about a year now. The only big missing feature I've found is notifications which in some ways is quite freeing and makes me check my phone a lot less.
LineageOS (and perhaps other ROMs) have the option to disable all networking features for apps, so I actually still use Google Camera, Google Photos (as an offline gallery) and Gboard (again all offline) and the majority of features just work. They don't complain about missing Google Services, nor about the missing internet connection.
There are great alternatives to apps like YouTube (NewPipe), Maps (OSMand), Chrome (Chromium, or I use a browser called Privacy Browser on F-droid) and I have tried apps like Spotify and they too work without Google services (although I guess some features might be lacking).
F-droid is an amazing service and has many FOSS alternatives to apps. I found myself today recompiling my browser application to fix some small bugs which just made me sit back in my chair and think "that is so cool"!
I think making the change can be gradual (for example switching to LineageOS for MicroG to get a subset of working Google services) before fully de-Googling, but the change is definitely possible (and easy) to make.
I use LineageOS for microG [1] and I'm planning to move to GrapheneOS once the Pixel 6 gets released (since it finally has guaranteed 5 years of kernel updates).
LineageOS is superb for getting rid of stock OS bloatware and spyware and I have an experience on it that's better than stock Android. However it doesn't have hardened security like GrapheneOS, which is why I want to move to that later. On the other hand microG is needed for push notifications and maps APIs, which GrapheneOS doesn't support so I'm not sure how the fallback options of some of my currently used apps will fare on it.
If microG turns out to be necessary for my workflow then I'll get CalyxOS instead, since it includes microG and is somewhere between LineageOS and GrapheneOS in terms of security.
From the sounds of it, the Pixel phones have the widest support across the different options here, so the Pixel 6 might end up being my first Android phone purchase in a while.
I am daily driving GrapheneOS for over a year now as my only phone on a pixel 3a and I like it quite a lot. Here's how I handle stuff and what limits i encountered. Keep in Mind that you have to rethink your app usage aswell, meaning testing a lot of apps from F-Droid to see what works for you. You average FAANG Privacy Invasion App dejour propably won´t work and i´d be wary of hardware requiring an app to be used if you go all in.
1. E-Mail: Using Fairmail from F-Droid (paid version though) is great for GMail and most other Providers. Notifications are usually faster than G-Mail in the Browser.
2. WebBrowser: Using Fennec from F-Droid with Adblock. The Chromium Version integrated in Graphene is propably more secure though. But adblock is life...
3. OsmAnd from F-Droid for Navigation. Works well enough, UI is clunky though. But Offline Maps are pretty sweet to have.
4. Most Messengers work, Notifications are spotty sometimes. Telegram Signal, Element, Threema all do fine though Element sucks battery life down to unaccaptable levels. Haven´t and won´t test whatsapp.
5. OpenCamera + Nextcloud is good for Cloudsyncing and Camera.
6. Password Management with AndOTP and KeePassXC is sweet and integration of the fingerprint sensor is really useful. Useful enough that i miss it on my desktop linux
7. Paypal App works, my Banks app work but YMMV.
8. Biggest annoyances are local german Taxi Apps. They all don´t work but i was able to work around it using a website. Still can´t pay via app.
...Well i don't use my phone for much more than that.
Battery Life is great, Security and Privacy is also good. You can lookup App Compatibility to a degree here: https://plexus.techlore.tech/
I'm using GrapheneOS on a second device for various reasons. The biggest issue for me is that not all apps work / run. However, I have limited app requirements, so that is fine. If you want to run all social networks, Uber, Lyft, and so on, there might be the one or other that doesn't work (I didn't try them all). However, you can always use the mobile web offering I guess.
In terms of classical smartphone features, I know what I don't get out of the box due to the lack of Google Services (Assistant, Picture Sync, etc). That wasn't an issue for me as it is a secondary device.
GrapheneOS now has https://grapheneos.org/usage#sandboxed-play-services providing the ability to install Play services in a sandbox. The core functionality is already working in the Stable/Beta channel releases. You can install it in a dedicated profile to avoid apps in other profiles being able to use it.
GrapheneOS is fine with people using Google apps and services but not integrated into the OS and they should be on the same level as other apps and services without any special privileges/access. We're working on making this a reality. Google could implement the fallback code paths we're providing for Play services themselves. All we're doing is teaching it to do what it should already know how to do. Perhaps a regulator can force them to unbundle their services and make them usable anywhere.
Not the person you asked, but my banking app works but occasionally will crash when I go to certain parts of the app. I'm not sure why.
Other than that Discord, MS Teams, and ProtonMail all work fine with the exception of push notifications (I disable those anyways, so this isn't a concern of mine).
I've been using /e/os [1] for a while and I am very happy with it. It has microG integrated so any apps that rely on google play services should still work.
[1] https://e.foundation/
I hardly use any apps that are not foss, really I just need slack and whatsapp, and they work well (push notifications etc) so microG works well for me (I don't think these 2 apps would work fully without microG but never tested that). Banking apps I don't use, and they probably wouldn't work, but hey, websites are still a thing.
CalyxOS on a Pixel 5 with microG for the past month. The only two problems I've had have been that I can't install the CapitalOne app and I can't install any paid Google store apps. I have a backup Android phone (Unihertz Jelly 2) with LineageOS and Google Play Services / Play Store installed, which I haven't had any issues with at all. I don't use Google Pay, Google Assistant or Google Maps. Those three apps are my biggest pain points, but a sacrifice I'm willing to make. I do use Garmin Pay on my Garmin watch and the Google Maps web app.
I’m interested in moving away from Apple and big tech in general, but I don’t know how practical that is yet.