ah ok! i have a fiio btr3 bluetooth receiver that is something along those lines. it doesnt show any track info but its got buttons at least and you can plug in whatever headphones you want. there could be others around that are more like the MD remotes but i havnt done much research
if youre on android theres also “key mapper” by sds100 that will let you change to the next/prev track by long pressing the volume keys so you dont need to take it out of your pocket!
ive been using floccus for a few years now and no complaints
i havnt tried syncing tabs but i think its an option. what i do have is a one-way sync job for the tabs in each browser so i at least have a backup of them, and each browser has its own file, but i would imagine if you tried to sync the same file between multiple devices it would just get very messy at some point