I think to keep any YT channel fresh and watchable, you need (at least) two out of three things: detailed information, somewhat controversial/debatable opinions, and/or humor.
1. information: It might seem redundant, but a lot of WMMA fans (myself included) don't keep up with fighter updates on social media. So, just collecting that data, summarizing and presenting it in an easily digestible form would be helpful.
2. opinion: sometimes a YT video can generate a lot of buzz with an opinion or clash of opinions (which carries over into the comments). Someone recently wrote about "Nunes being/not being the WMMA GOAT". Great topic with a lot of possible avenues of discussion: what's more important in determining this criteria? 20+ wins? Wins over other high-level fighters? Meteoric rise/aura of invincibility? Long winning streak? Few losses? All losses avenged? Multiple-time champion? Compare and contrast various candidates. It will probably bring out some fan-boi-ism, but it could also inform some people too. Maybe cover a potential GOAT candidate with each episode and add something like at the end like, "Amanda Nunes might not be the GOAT now, but if she does X, Y, and Z, the crown is hers for the taking." You could just as easily include segments about rising stars. Suarez and Ladd are on verge of taking over the UFC but most fight fans don't know much about them
3. humor: I don't know what you sense of humor or delivery skills are like, but they can spice up a show. Even just the occasional WMMA fans only will get this joke kind of thing could be a lot of fun.
4. Lastly, keep you videos short. Most of the people making MMA videos on YT know seem to deliberately keep them under 10 minutes and included all three of the criteria I listed above. I should point that I not an expert on this things, but these are just my insights based on what I've seen. I think a thick, solid, tight (8-minute) vid with 2-3 minutes of collected social media information would be a good start...then a opinion of the week segment with 2-3 minutes and even multiple contributors to get the discussion rolling....maybe a "blast from the past" segment featuring some now forgotten pioneers for WMMA pre-Rousey....maybe a most anticipated fight over the next two weeks (and why)...and a joke at the very end.
Anyway, that's my overly-long-winded basket of ideas. I hope you are super successful.
Jarl