Odd opinion, but the only boxing I enjoy watching in general is Olyimpic boxing.
3 rounds is sufficient to guarantee that guys won't take rounds off for 'tactical' reasons and mutually try to engage.
Some professional fights can be watchable, but I find your description of boxing being a 'circus' very relatable.
Want a whacky walkout in a feather robe or a robot costume? Fine with me, but what are all those 150 people doing inside the cage after the fight.
2 fighters, 3 cornermen each, the announcer and a camera guy would be sufficient. But all those greasy, slimy, peeled ass managers and other clout chasers need to be in there so bad that the whole thing ends up looking like a club party on the Cote d'Azur.
I just find it offputting to a degree where I'd rather not watch at all.
The lack of promotion is a factor as well. They have built up a system where the records are so padded, that the only guys even worth mentioning in general media will be world champs on long undefeated streaks. So you'll end up with one well known champ every other weightclass with 4 (I hope that's right) world champs at each single weight. There are too many organizations and too many weightclasses.
Now you have a whole lot of champs, and the public attention has to be distributed between all of them. So the individual fighters will get less attention on average.
Being a casual fan has become too much of a hassle.