Sync on Android for Lemmy is also giving 404 error to me for the last 4-5 days. I have been using Jebroa instead, which is not as good in my opinion...
I started with Memmy, but then started favoring Voyager, which was said to be the closest to Apollo in functionality and design. Then i noticed that Voyager always omitted comments from a certain instance, so I’d only get one side of the conversation, so I switched to favoring Mlem, which I’m really enjoying at the moment.
Now that I’ve given it a try, I think that I would continue using Mlem even if Voyager fixed that particular issue. It has a really nice level of polish and hasn’t had any issues with crashing, unlike Liftoff or Thunder, which I’ve dropped completely.
When browsing comments on Lemmy, I would see what looked to be top-level comments that were clearly replies to another comment, but the comment it was responding to wouldn't be displayed. After this kept happening, I decided to try viewing the thread through another app (i may have been using an account from another lemmy instance, which I'm guessing may be pertinent) and then I would be able to see the actual top-level comment that was being responded to.
Liftoff is awesome, but it's not compatible with 0.19 so any post from instance with latest update will not load. I switch to Boost and while it has problem, it's awesome too.
Eternity, also known unofficially as Infinity for Lemmy is another good one. It functions the same as the Infinity for Reddit client but for Lemmy instead. It's still early in development but it has gotten much more stable.