Hi @AdeZwart ,
The possibility of deactivating PR comments and keeping only the Quality Gate status is something we are looking to, not in our close scope for now (no ETA though).
We are also interested in having the passing Quality Gate as a required policy, so PR’s are blocked when they don’t meet the gate.
If I understand correctly your use case, you can do that by setting a “Status Checks” branch policy on your main branch. You will find the SonarCloud Quality Gate there.
Hope to help 
Kind regards,
Christophe