^ Yeah, it would be wiser to just continue the discussion in the thread that is already in place, if the question is not out of reach of the previous one.

And, definitely - there is no man that would be in his position and say - "today I will buy 1 mil. BTC.
Because I can  ". That's nonsense.

Take it easy Op, the bitcoin market manipulations is not like that of the stock market where monopoly economy polices is practiced just to favour a particular trader.
For a billionaire to buy a million of bitcoins is possible as long as he has the money and while the supply bitcoin might not be sufficient to purchase such an amount of bitcoin considering the total number of bitcoin invented and the mined and unmined bitcoin, the Investors can always Dca in buying and accumulating gradually until he get to his limit of purchase.
Indeed Such value of purchase can cause a pump to the market when dump (hodl) but does not give the investor the hands to control the market because it is not a regulating market like the physical trading market.

You mean to manipulate the price? Not at this point, maybe in the early years of Bitcoin, but now that the volume is too big, that not even a billionaire can manipulate it's price to it's favor. As I have said, the market is one all over the world 24x7 and it's very hard to create some manipulation.

On the other hand if someone tries it, maybe it might turn out bad for him and instead of making profits, he might have lose a lot of money along the way. So not only it's not possible, it's not also advisable to do not.

Possible, probably half of Bitcoin are owned in centralized exchanges, so billionaire can buy Bitcoin through CEX without need to move the coins. If both billionaire and CEX didn't publicize if the billionaire bought Bitcoin, no one will know it.

Bitcoin market cap is really huge, it's worth $1 Trillion. But if few billionaires agree to use their money just to buy Bitcoin, they could own more than 50% of Bitcoin.

The "Pools" that you may be talking about are the centralized exchanges. This is where the most selling and buying takes place and it is where manipulations are likely to take place because everything is done off chain, and we can't know for sure who bought how much unless if the exchange decided to publicize it.

If depends on the kind of exchange the counterparties possess. if it's a decentralized exchange like bisq, thenyou are right, but most of the miners end up depositing to centralized exchange wallets.

manipulation do sometimes happen, but there are some things we many never know. The worst is when manipulation happens and such news breaks out, or when someone is about to sell a huge amount and the community gets to know. People tend to panic sell leading to a shake up in price.

[Did you know?] Bitcoin Table of Units

There is no staking pool or liquidity pool for Bitcoin but if you want to buy or sell bitcoin, you have to do it Peer to Peer directly with your trade partner or do it with a middle man with Escrow service to make sure both buyer and seller of a trade will be safe in P2P marketplaces, or a last option is buying it on a centralized exchange.

Your bitcoin is stored on blockchain, but if you buy it through a centralized exchange, you don't own private key, you don't own your bitcoin. You can see bitcoin amount in your account but it is only a credited number, and you will only own that bitcoin after withdraw it successfully to your non custodial wallet.

Reminder: do not keep your money in online accounts

There is market manipulations but Bitcoin is not a pump and dump coin.