I'm surprised to hear you say that. I've played the most demanding Android games on the Pixel 3a with no issues. I've never experienced anything but a butter smooth UI on Graphine or Lineage to be honest. The battery life has been all day for me even when using GBA emulators for multiple hours a day.

I agree the default camera app of Graphine isn't great, but it's picture quality better than the iPhone I came from (iPhone SE gen1)

Can you install GCam as apk from somewhere? Will it work? I use GCam on the default Android (8) on my Nexus 6P and it works well. I am thinking of upgrading to Pixel 2XL or 3A and install Lineage OS with GCam, so I believe it would be a much better experience than the default ROM on a Pixel. But I have no idea whether GCam would work in LOS.

I use this: https://github.com/lukaspieper/Gcam-Services-Provider to make the GCam app work

You should be able to get GCam via Aurora Store by setting the spoofing to a Pixel device, but newer versions of GCam check for something that cannot be spoofed with an app (issue #22 in above github) so you have to get a modded GCam app if you want to user newer versions and use an android rom that does not spoof this.

The mid-level processor on the Pixel 4a may just not be performing to your expectations. A phone with a high-end processor would perform better. For GrapheneOS, the fastest compatible phone available (used/refurbished) right now is the Pixel 4 (or Pixel 4 XL).

Also, if you are using a Pixel phone with a non-default flavor of Android, the Google Camera app still works if you download it manually. APKMirror is a trustworthy app source run by Android Police:

https://www.apkmirror.com/apk/google-inc/camera/

(For Pixel phones using an older Android version, you may have to use an older version of Google Camera if the current version does not work.)

Pixel 4 running graphene. I'm sure it's fine by android standards, but if you're used to iOS, it is unbearable.

Going back to iPhone as soon as I've got some free time to get everything set up again.

Unrelated, but I'm still very surprised there's no standard way of doing live photos on Android. They really do add a lot to the experience of reviewing old memories and Google has had at least 5 years to catch up.

Software patents are often used to stifle competition.

It performs worse than my 10 year old iPhone 4S. It really shouldn't have to.

On my Nexus 6P I use GCam v. 5.2.019.188906351 and it performs really great! It is quite slow with HDR+ (but usable), and almost on par with the default camera without HDR+ (still producing great camera quality). I am curious whether the experience is similar on a Pixel line, with Lineage OS (or any other custom ROM).

>very poor GPU hardware acceleration support

Pretty sure GrapheneOS doesn't do anything to change GPU h/w acceleration.

Pretty sure GrapheneOS didn't even engage with GPU HW acceleration. Everything felt like software framebuffer.

This in fact sounds quite exaggerated. I've had nothing like this experience with the Pixel 4a. Battery life has been exceptional, UI works fine, Play Services work with about 90% of the apps I tried. Google Camera worked also with Play Services so you don't have to use Open Camera.

I run GrapheneOS on a 4A with TMobile and the frequent reports of people trying to call me telling me my line is out of service and days where calls won't initiate from my phone at all makes me want to run back to my iPhone.

The tethering seems to be pretty flakey as well with me often having to reboot the phone.

I've been using GrapheneOS on a 4A with TMobile as my daily driver for over a year and have had none of these issues. Never had an out-of-service notice from someone calling me, never had a call not initiate, and tethering works great.

Maybe it's something to do with OpenGapps? I never installed it or microG, I'm perfectly happy with just Fdroid.

I'm running GrapheneOS on a 4a right now and it's smooth like butter - maybe you needed to wait for a few updates. The camera has improved a lot as well but is still not close to the stock google camera.

It seems like what you're looking for is CalixOS + microG.