[mr_toad]

I think it’s true that once an event horizon forms no physical force (known or hypothetical) can stop a singularity forming.

There may be some form of very dense matter that stops large stars from collapsing to the point where an event horizon forms in the first place, but that doesn’t seem to apply to super massive black holes.

For super massive black holes the event horizon grows too fast.

[naasking]

Singularities are a deficiency in GR, they don't really exist.

[GoblinSlayer]

It takes infinite time for event horizon to form, before that it's just dense. It's time dilation that stops formation.