I did not hear about KDE connect (maybe because I do not use KDE), but had the exactly same need (control mpv from my couch). I have found this: https://github.

I did not hear about KDE connect (maybe because I do not use KDE), but had the exactly same need (control mpv from my couch). I have found this: https://github.com/ndunks/xdotoolweb https://github.com/ndunks/xdotoolweb - I only have one use case so I only run it - using a simple shell script wrapper - together with mpv. It working fine for me, and it does not need a client on the mobile (except a browser), also it is not connected to the KDE ecosystem - if anyone else needs some lightweight solution for the same problem...