I'm reading many people complaining about the app being abandoned, not being updated for a long time.
Have you tried contacting the developer with your issues?
They last replied to a review on Google Play on 13th Jan 2025. Someone else also mentioned that they received a response via DM. So the developer is definitely still alive.
The app is free to use. It's great if you chose to support the developer by paying for the ad-removal or subscription. Unfortunately, I don't believe the user base is large enough to allow the developer to work on it full-time, or even part time.
Personally, I think Sync is a passion project, hence the original Reddit version was so good. The downside with passion projects is that you work on them when you have time and inspiration to work on them.
I guess what I'm trying to say is that all the negativity won't help inspire the developer to dedicate more time to the project.
It would be more helpful to compile a list of bugs and issues, and forward them to the developer.
A couple of things happened for me. One was switching to a specific instance that wasn't my own and finding that posts just disappeared. I then forced the app to stop in settings and went back in. Nothing doing, no posts loaded. Then I signed out and signed back in. No luck, same result. I had to uninstall and reinstall to get the app to show content again. Then there's the random replies that go missing or don't show up in the inbox but are there when I go back to the post and magically after I see them in post they show up.
A lot of the time I will look at a post and it doesn't log it as being read. Or it'll log all posts and being read and then I end up not being able to load more posts (despite my settings not having scroll to read enabled). I've gotten the no comments on posts with comments. I've gotten the ghost comments with no text. There's been other stuff too.
I never know what glitch I'm going to encounter.
I have experienced the not automatically Marked As Read bug, but not the others, but I'm also not that active on Lemmy yet.