The general consensus is that extension owners should have a way of providing extension builds themselves over github, and these would be βTier 0β. This is already something we can set up for python-only extensions, but with the github actions work that is currently being done it is also becoming possible for C++ extensions.
In the meantime we can reduce manual effort by gating extension index PRs by only copilot reviews, where copilot is instructed to be picky only about security issues.