The number of executors on our Jenkins master is set to 0, but there seems to be no limitation of the number of concurrent multibranch-related operations on master. Is it possible to somehow restrict the number of parallel operations happening on master?

We have an increasing number multibranch pipelines that keep our Jenkins master constantly busy. There are many periodic scans (projects define them typically every 5 - 15 minutes) and many new branches that cause load on the master node due to git clones.

Yesterday, we restarted Jenkins and it was totally irresponsive for the first 30 minutes. After it calmed down, we saw that only a few jobs were running on our agents, but the master was completely overloaded with multibranch-related operations:

Is it possible to limit these parallel scans so that they don't overload the whole system?