Limit the number of request per library
Similar to how you can limit the number of request for a patron by group.
If a library has limited resources (labor and materials) and can only serve so many of those request within a given term, it doesn't help to have a backlog, especially when interest in a given item will be lost over time. In helping libraries to mitigate demand it would be good to set a limit on the aggregate number of request received by a library. When the quota is reached then the requests option in Primo would grey out. or not appear. A label or messaging could be made available that advises users that capacity has been reached for the library.