So we got Free version of Plexamp :)
I use symfonium too. Great app. I’ve stumbled across some bugs here or there but that might be due to my setup and if I actually bothered to report them, I imagine the developer would be quick to fix them. At least he was fast to reply the last time I opened a ticket.
One great thing I like about Symfonium is the aggregation of multiple libraries. You can add a plex, jellyfin or subsonic API compatible server (like navidrome) simultaneously.