I recently switched to BasicSync as well. I had Syncthing-Fork from the F-Droid. Then I switched to the Play Store version. For whatever reason, it wouldn’t keep connection to my server. BasicSync is always able to reconnect and I was easily able to reuse my previous Syncthing-Fork config.
Do you have a domain? If you do, maybe try Nginx Proxy Manager and SFTPGo. I previously used File Browser but the developers made some fairly large breaking changes and I never went back. SFTPGo lets you add accounts easily and I have specific folder setup for sharing with friends. It has a clean interface too. If you don’t have a domain, maybe try Tailscale?
I haven’t heard of it either. Looks like it maybe has additional features built on top of Aurora Store. At first glance, App Lounge seems very unintuitive to install. I think I’ll stick with Aurora Store for now.