I also have a question about what will happen after 21mln. bitcoins mined, but a specific one.

2140 year. Imagine the last bitcoin has been mined. From now on, it is impossible to get a new BTC, which means that all bitcoins that will exist at that time (to which there is access) will already have a history on the blockchain. That is, it will not be possible to get a "clean" btc and all will have owners in the past (most likely different), except for those that have not moved (but have access to them). Over the years, each bitcoin will go a long way and change not hundreds and thousands of its owners, so it will not be possible to say who owns it now. Will bitcoin be able to become more anonymous in future years (provided that the privacy of the owners is respected at every stage)? What are your thoughts on this situation in general?