you have to be careful who you call "experts"! most of those whom you see online spreading bullshit pretending to be "experts" are either idiots trying to make buck or actual experts that are spreading misinformation to make millions.

as for ETF, i think at some point in the past people disagreed about whether it is going to be approved or not but now they all agree that it is not going to be approved anytime soon as we have all seen how SEC rejects all of them and is not planning on changing their course.
as for the "bull run" since the market is ready i'd say if an ETF was approved it may help start the bull run unlike before when market wasn't ready so its effects could not be anticipated.