@Mark15
1: Yes, assuming a measurement is too difficult was a mistake.
2: Do we have enough evidence to be sure it's a particle ring? Tidal forces are pretty well understood.
3: What do you think of Ethan Siegel's take? "The authors are assuming the existence of a coupling that isn’t [necessarily] there and ascribing the perceived evolution of the black hole-to-stellar mass ratio to [it]"
https://bigthink.com/starts-with-a-bang/black-holes-dark-energy/
@fuy Thanks, I'll give Siegel's article a read.