How exactly do SMBHs in the center of galaxies form

[PeterDonis]

Centrally symmetric mass distribution cannot emit gravity waves even when changing.

This is true, but no real collapse process will be exactly spherically symmetric. If it's not, it could have a time-varying quadrupole moment and emit gravitational waves.

 

[ebos]

When I posted this I had just read an article from a team actually studying our black hole After posting my comment I went back and for the life of me cannot find the page. Apologies but the woman in charge seemed quite optimistic. Next time I will start a better system for saving these articles better in order to provide the link.