Arr and stremio serve different purposes. If you just want to watch content yourself then do stremio.
If you want to keep certain movies yourself and want to supply a streaming service to friends and family then arr is better.
Arr has ability to watch your content with no internet.
If your into foss software arr is also way to go
Nice. Just want to point out that there is jellyseerr for jellyfin as an alternative to overseerr.
There is also reiverr which is new which allows managing sonarr,radarr, and jellyfin (basically it providers an interface to watch jellyfin content and also add episodes and movies to sonarr/radarr. I use reiverr for me as admin but it doesnt do requests as of now so i keep jellyseerr for my users
There is also watchtower on docker that automatically updates your images
And finally there is rdt-client (real-debrid torrent client) which is a real debrid client that pretends to be qbittorrent and allows sonarr/radarr to download from real debrid instead of torrenting it