Can I set response header on /cdn-cgi/ paths?

Since Cloudflare adds and manages the /cdn-cgi/ endpoint, it makes more sense to address this on their side with a X-Robots-Tag: noindex, nofollow response header.

Adding this header via a custom Response Header Transform Rule does not work, since (again) Cloudflare manages this endpoint and does not allow any alterations (which makes sense).

macs@my-macbook-pro ~ % curl -sI "https://mywebsite.com/cdn-cgi/" | grep -i "x-robots-tag"
macs@my-macbook-pro ~ % curl -sI "https://mywebsite.com/cdn-cgi/" | grep -i "x-robots-tag"
x-robots-tag: noindex