The listprovider reponse time is very slow, lags, when the options in the lists are large.
Possibly consider reintroducing version 1x style metadata input helper to optionally create filter list on demand. 5x creates all metadata filter list options prior to use.
Example 1x style list on demand query for term 201901 series title "Introdu"
WARNING: 1x admin-ui used Series Service directly for series metadata.
In the meantime, group list from September recomends abandoning expensive listproviders: https://groups.google.com/a/opencast.org/forum/#!topic/users/ixjyVDphLR4