This didn't happen to OP, and it isn't recent - look at the report date.
This happened back in 2021 and apparently blew up on Reddit and Twitter, causing OpSec to release a public statement that claimed that the DMCA notice was a fake.
https://news.itsfoss.com/ubuntu-download-dmca-notice/
https://torrentfreak.com/opsec-says-dmca-notice-system-was-spoofed-to-target-ubuntu-download-210527/
OP is clearly not that if their use case involves a homelab and docker containers. Arch is a perfectly valid suggestion here.