Just stop giving them money, give it to some other project which is also doing something valuable but which needs it more. If it ever turns out the Wikipedia needs your money urgently to keep the servers running, start giving to them again.
If they run out of money to run the servers, I'd consider that a good thing.
Someone can start a new "wiki-2" project, starting out with a wikipedia dump as a base, and continuing to be a free encyclopaedia that anyone can edit, but without the $150 million dollars of expenses - I think you could host wikipedia with 2 members of staff and 5 servers, plus cloudflare for the 99% of read-only requests - similar to how they ran it at the start of the project.
Maybe its time for a leaner alternative?
I can't say the same for other enshittified companies.
I have a belief that they're caught in a very bureaucratic "we need to use your budget otherwise it would be put into question", but it also means when I give 1 euro to them it goes less and less to their core mission I want to sustain.