Enabling compression in a hosting panel does not establish what visitors receive. Inspect the response at the public delivery route: a proxy may behave differently from the origin server.
For an owned public test address, inspect negotiated delivery with:
curl -sS --compressed -D - -o /dev/null https://example.invalid/
--compressed requests supported compressed responses and handles their transfer accordingly. Available methods depend on the curl build, so failure to observe Brotli does not automatically indicate a server fault.
Compare the appropriate measurements
Inspect Content-Encoding, content type and transferred bytes in browser network tools. Repetitive HTML may compress very differently from an already compressed image. Avoid assuming one policy suits every asset type.
Check that cache variants reflect relevant request conditions. Incorrectly mixing responses can matter more than the difference between two compression algorithms.
Compare a homepage, a text-heavy article and a stylesheet using the same delivery route, noting any CDN. Record transferred and decoded sizes separately. Depending on the browser, the network panel labels them “Transferred” and “Resource size”.