ceramics Could you take a note of which apps are slow to update? Or is it all of your apps?
I haven't personally noticed this, but to be fair I usually don't look at the update process to finish; I just hit the update button and swipe to another app while Play Store does its thing.
Note that GrapheneOS uses something called Ahead-of-Time Compilation, which results in slightly longer app install times compared to operating systems that use Just-in-Time Compilation (such as stock PixelOS). Summary here.
Some apps will take significantly longer to install; one app that comes to mind is Revolut. But if all of your apps take a long time to install/update, it might be interesting to have a list of those apps so people can compare install/update times (although understandable if you don't want to provide this).
By "long" install times I mean several minutes.
ceramics or eventually throws an error.
I have noticed this occasionally, but for me it's resolved by attempting the update again. It seems to usually happen if I check for updates and hit the install button, but then swipe the Play Store window away before the installs start or finish, then open Play Store again. Actually I now noticed that App battery usage for Play Store was set to Restricted. I'll try setting it to Optimized and test over the coming days.