Is there any remaining discussion over the existence of supermassive black holes at the centers of galaxies, or is science in complete consensus on their existence?

And by complete consensus I mean no fringe theories whatsoever that say SBH don't exist. I'm curious to know how much discussion is ongoing on this matter or if it is completely settled.

I'm not interested in discussing the scientific evidence for SBH. I just want to know what other people are saying about this, or if no one is saying anything at all.