i am currently using a very rudimentary player that is extremely lightweight, vanilla js, supports basic multi-room (multi-device, i.e. pick a track on your phone and listen to it from the tv) and defaults to repeat 1 mode. I want it to run without issues on old phones so i can just hook one up to the stereo. Considering adding drag and drop so i can listen to local tracks as well

(you clearly need some sort of server to do this, i am using mqtt because that's what i had laying around, but maybe this could be feasible with modern browser features skipping an external server?)