> I live in Europe and I do trust my ISP (and government, which has a decent track record at enforcing GDPR).
I believe the GP comment was referring to government surveillance. This is a thing in Europe and GDPR won't protect you from it.
Also, good news for you: Since you live in Europe, the announced switch to DoH with Cloudflare as the default for Firefox users in the US won't affect you.
Even with DoH, my ISP already sees all of my network traffic. My DNS queries will effectively be anonymized by their recursive name servers.