Windows Media Player is legacy software - Microsoft even calls it Legacy Windows Media Player.
'Legacy' means that the software is old and no longer being developed. In time it will be discontinued.
Most people today are not ripping CDs and making music libraries - the original use case for LWMP - and so it no longer made financial sense for Microsoft to pay a substantial license fee to Gracenote or MusicMatch who provided the metadata. Microsoft ended its contracts with metadata providers in December, 2026. Since then, LWMP does not provide any metadata.
There are still third parties that provide the metadata, some for free and some charge for it. In the past I have used Exact Audio Copy with success.
BTW, something else LWMP no longer does is sync to MP3 players, because hardly anyone uses them anymore, and that saves Microsoft from having to pay royalties.