Solarmass thank you so much.
will keep you in the loop. the command you set it to was flatpak -spawn as the player then /usr/bin/mpv and --host as the arguments and that did not work.
most of the thread assumes this is flatpak freetube trying to communicate with flatpak haruna and flatpak mpv and that is not my situation. but I can't be sure, some are not assuming that.
but 1000 variables in this thread--everybody threw their hat in the ring the way I like it.
the first one failed. I will keep trying tomorrow.
up in 7 hours. must.shut.eyes.now. report back again
EDIT:
you're in budgie i'm in budgie
you have flatpak freetube and I have flatpak freetube
you have solus repo MPV as do I
show me a pic of your settings/external player page
ok back to sleep 🙂