I don't think this will affect Bitcoin's price, especially when there are other countries that are "miner-friendly". An EU ban would prompt miners to move to another region in order to keep their business running as usual. Just because most countries are turning their attention to climate change, doesn't mean Bitcoin mining will end for good. There will be a few countries that will allow Bitcoin mining, prolonging the life of the cryptocurrency. But you can rest assured that if PoW mining is banned all around the world, the community will simply "vote" to switch to a new "eco-friendly" consensus algorithm altogether.

Whenever the switch will degrade Bitcoin's decentralization or not, it's yet to be seen. I wouldn't worry about EU's "anti-crypto" policies as long as there are other countries supporting it every step of the way. Just my thoughts