Overseerr is basically a polished front end for Radarr/Sonarr. It’s useful if non-techies are requesting things, and/or you just want a single, dead-simple place to request (video) media. If you want to just try it out it doesn’t affect your radarr/sonarr setup at all.
@ShepherdPie@midwest.social gave a good explanation of Prowlarr. Just another simplification/automation tool.
I am in a similar boat. Since you have Tidal might want to look into Tidal-dl to “backup” the things you especially like in high quality.
Tidal is actually not too bad, and it pays artists more than other services (not a lot, just more) but I do expect it to go downhill/away eventually so I make a habit of downloading what I can and supporting the artist directly in other ways.