In the world, the wealthy become wealthier, the poor become poorer, the middle class disappears. One of the reasons of this is the inflation: it is a kind of regressive tax, this tax is paid mostly by the poor because they loose their savings, while the wealthy keep their savings not in money but in assets. So, since the bitcoins are a way of keeping the savings, they can fight inequality to some aspect.
A little note: the decrease of the size of the middle class is not happening in the whole world. In China and India and some parts of Africa the middle classes are growing, probably by much more (in terms of population) than they are weakening in Europe and the US.
Anyway I agree with your general sentiment here: the "inflation tax" indeed benefits the richest 5% much more than the rest of the population because it fuels the value of their assets. (In some cases however, real estate is also appreciating, which is often owned by middle class people, but that's probably a small effect.)
And I also agree that early Bitcoin adopters in some cases have taken their chance to become a new part of the 5% richest, so there are at least some new groups in the elite.
Now: will Bitcoin profits really trickle down into the poorer classes, apart from those who were already "smart" and have already invested? I think this is a tricky question to answer.
First, the biggest Bitcoin gains were already made, even if Bitcoin reaches the million USD, it is a 900% increase, and we had already much steeper increases before (100k+% in a few years, e.g. 2012-2017). 900% is approximately the growth since the 2022 low, at least in the same order of magnitude. I also expect that the step from 100k to 1M will take at least a decade. Volatility is decreasing, and the bull markets are weaker every cycle.
Second: the masses of the poor will be probably (in a general sense, "some smart poor people" already invested of course) the last group to be able to invest in crypto because they don't have too much spare money for that purpose. So they would perhaps invest when Bitcoin is already at 800k, and have only 25% profit until the million.
And third: it is possible that an "unproductive" asset like Bitcoin could damage the profits of productive assets like stocks if the market overheats too much and everybody is trying to get Bitcoin. I think the probability is low for that (due to the reasons I already mentioned, in particular the lowering volatility) but it is not impossible. This could lead into businesses get bankrupt and rising unemployment.
IMO thus, regarding poverty reduction, I would expect much more from the "inflation reducing" qualities of Bitcoin than of an extreme bull market taking us to 1M.