>

no but at least make it enjoyable
Does every video HAVE to be funny tho? >

no but at least make it enjoyable >

Some definitely seem forced. Two funny people aren't necessarily going to be funny together. 
There are some good collaborations though. I follow a few fitness related YouTube creators and their collaborations are cool.
Recently Adam Ragusea (cooking YouTuber) was on Renaissance Periodization (bodybuilding channel) and it was such a fun collaboration. >

So you want something new but don't want new people in videos together >

What are you doing step-youtuber? >

Seems more like a problem with the youtubers you've watched...
I do agree though that some youtubers add nothing by collaborating especially in reaction based videos, but there are some good examples out there of youtuber collabs that actually end up funnier (IMO) than if they were just by themselves. I feel like Cody Ko's "Thats Cringe" series with Noel Miller is one of the best examples >

Does every video HAVE to be funny tho?