The unsigned (FOSS) Apps aren’t removed yet. They will be removed by 2026-09-01. Removing --no-quarantine before that seems counter productive. And quite frankly removing unsigned Apps at all seems like a stupid idea. Homebrew is a third party package mamager, why are they precapitulating to Apple?
Third party taps (or are they fourth party?) will step in. You can run xattr -d com.apple.quarantine in the .rb file.

Relevant links.

• Homebrew Github Discussion about unsigned app removal.
• How Freetube bypasses the issue in their own tap.