[...]maybe in next few months one of them will successfully acquire millions of Bitcoin and this will create lots of noise in crypto space.
Take into account that while there are lots of Bitcoins on the markets (around 100-900k per day are sold, although some of course are traded several times per day) the more BTC are in the hands of centralized entities, the less are available on the free market, i.e. on exchanges and OTC.
That means that if the rhythm of purchases is very high (e.g. >20.000 net inflows per month) eventually there would be a significant influence on the exchange holdings. This will lead to less and higher sell orders. That does not necessarily mean the price goes up (even if it's likely). It can also have the effect of reducing the exchange volume and thus slowing down both the ETF and MSTR acquisitions.
So I believe there will be some natural ceiling of the holdings both of ETFs and MSTR. I estimate it close to 5-7 million in total, if we take into account that about 3 million are assumed to be lost (including Satoshi's coins), 3 million are on exchanges, and currently there are about 1.5 million in ETFs and 1 million in company treasuries. 10-11 million are currently believed to be held by individuals. These 10 million may reduce to 8 or 7, but not much further, because many of these are believed to be long term hodlers.
We would then arrive at a structure with 4-5 million owned by ETFs and other derivatives, 2 million by MSTR, 3-4 million lost, 2-3 million (a little bit less than now) on exchanges, and 8 million held by private owners (total currently is ~20 million). But that is the maximum I can imagine, and hopefully we'll not get there.