DoH working fine on AdGuard Home, but enabling encrypted DNS in Windows breaks Proton Drive and Steam Cloud saves

Hi everyone! I'm new to Reddit and to this sub, but I've been self-hosting apps for a while now.

I installed AdGuard Home in Docker on a Raspberry Pi 4 with 8GB of RAM, dedicated only to this. It's running great, so I decided to enable DoH locally. I pointed a real public domain name to my Pi's private IP and generated a TLS certificate via Let's Encrypt using a DNS challenge; that part works fine, and I've also done the necessary config on the AdGuard Home side.

However, I noticed that as soon as I enable encrypted DNS in Windows settings, everything breaks: Proton Drive can no longer connect to the internet, and Steam fails to load cloud saves.

Any idea what could be causing this? Has anyone run into the same issue?