The Jenkins version includes the global discard jobs function, but it doesn't seem possible to override the function as shown here:

https://plugins.jenkins.io/build-discarder/

This problem has already been reported here:

Local build discard settings is not overriding global build discard settings(Default) - Using Jenkins - Jenkins

What seems strange is that this plugin doesn't seem to be necessary because Jenkins natively has the Global Build Discarders function.

Manage Jenkins >> Configure System >> Global Build Discarders.

Has anyone already encountered this problem and is it a bug? For information, adding the plugin doesn't change anything.