I don't know if there was just a crap ton of blue hypergiant stars in the early universe that crank through the fusion ladder in a couple million years, it wouldn't surprise me.
There are the chemistry problems but the big one is "how did supermassive black holes get so big?" Webb is finding what seem to be huge black holes way back but the black hole problem has been around for at least 25 years if not more.
Supernovae can create black holes in the 10's of solar mass range and they can merge but it would take a long time for those to find each other to merge to the 60 billion solar mass range. You might have processes that make 10^5 solar mass black holes but it would still take a lot of time for those to find each other and merge to make supermassive black holes.
