They can only know who is using which crypto if trades are settled through a KYC-compliant centralized exchange. But outside of that, the EU will have a hard time trying to identify privacy coin users. Especially when its comes to a coin such as Monero. Buying/selling on a decentralized exchange, non-KYC P2P trading platform, or even F2F/in-person will render governments' efforts useless. Just avoid converting your privacy coin back into a transparent cryptocurrency (eg: BTC, ETH, stablecoins, etc) and there should be nothing to worry about.
This is actually good for crypto because it encourages decentralization. The inverse would happen if regulations are eased. As far as I know, not many people use crypto in the EU (compared to the US). So nothing will happen after the 2027 ban.

I don't see it the way you do. What good will it do to have a privacy coin in the EU? Unless you want to buy stuff on the Deep Web, it's not going to do you any good. I will be able to buy it in a DEX, but I won't be able to spend it directly and if I want to sell it, everything will be problems. If I buy and sell a lot through DEX I will have a series of transactions to my bank account that I may be asked to justify and I will not be able to justify. Meeting in person has its dangers.
I don't see why I would want to buy a privacy coin then. To make it so private that I can't even spend it?