I noticed that testing 3.0.18.0 Release Candidate there is a new UPNP library (larger size over 1M, filename: libupnp_plugin.dll)
in C:\Program Files\VLC\plugins\services_discovery folder that does not display any DLNA Servers under UPNP.
Replacing it with the DLL from 3.0.17.4 release (signature from: Donnerstag, 24. März 2022 11:08:57, 997k) DLNA-Servers in local network will be found again.
(Posted this in the wrong category before cos the issus happened before on android. Current case is with the Windows version.)