in longer runs for example super mario odyssey any%

is it okay to have like a show or video running in the background to watch while waiting for the unskippable cutscenes because theres alot?

you can of course have something playing in the back. note that for some games the rules disallow the runner from having any other sound than game and possibly mic

Unless the rules states that you need only the game audio there's no reason for the mods to reject your runs if they have extra audio.

However I wouldn't advise you to have anything that can be heard / seen in the uploaded run, shows / movies / music / podcasts / random videos might get you a copyright strike (potentially a community guideline / ToS strike as well if it's questionable enough) and potentially might get your run invalidated as well (muted segments / removed videos / game audio being covered by the other thing you're listening to). You should instead make a virtual audio cable setup so that only you can listen to that secondary audio, if you're very lazy a phone, tablet, secondary computer or whatever else on the side works too as long as it's not loud enough to be picked up by a microphone if you do use one.

Edit: Here's an example of why you only want your game audio on a run upload Notice how it's not on the boards despite it being submitted? https://www.speedrun.com/acecombat3