tbf, the stagnation is kinda expected. mura is the only person that makes 2d bestiality animations for years, there's no one else equal to him so it makes sense he's being a little lazy right now.
though i would prefer if he goes back to using other characters from other media instead of just making new OCs.
I wouldn't really say it's the lack of "competition". Plenty of artists improve by themselves whether it's for passion or to try and get more fans. It's not like Mura has already captured the entire potential 2D bestiality animation market. I think he can certainly get more fans if the overall art quality improved. Not that it's exactly bad rn, but if it was only still images then his works would be kinda mid in terms of appearance.
I think stagnation is a general issue with a lot of artists that put out monthly content. They have consistent output every month but it also leaves no room in their schedule. No time to focus only on improving their art whether it's learning a new technique or refining their current process. I find that the artists that improve more are the ones that sometimes take an extra month or more as needed to release their next work.
I wouldn't mind if Mura took a month off or reduced the quantity of videos released to spend more time to improve the quality of each one. I feel people would still come back to support after a break, maybe even maintain their subscription during the break. Though I don't know their situation so maybe they'd rather not risk anything and take the stable income they currently have.