Hello @keithazzopardi,
Right now it’s not possible to configure Long Lived Branch regexp at organization level.
If you really have a lot of projects you can script that with the SonarCloud API
https://sonarcloud.io/api/settings/set?component=<projectKey>&key=sonar.branch.longLivedBranches.regex&value=develop|(release/.*)
I’d say there is little chance for this to change. We rather lean towards a unified concept of branch (no distinction between LLB and SLB), like in the SCM, which would render this regexp to distinguish the two obsolete.
Olivier