However, AFAIK, this problem would not apply to the NextCloud app.
I was a bit surprised that the official client suddenly disappeared though.
The official maintainer of syncthing-fork indeed stopped publishing to Google Play, but it seems some other guy is doing that now for him.
Here is when syncthing dropped the official Android client [0] so you can read through their rationale and the HN response at the time.
I am not an Android developer but I do follow this space; I had the impression at the time that it really was mostly about the dev cycles that would have been required and nobody willing to do the work.
I do wonder why they don't just make the fork an official Syncthing project, it seems like the obvious solution would be to officially bless it. I can only guess the maintainer likes their independence.