Anything by the Tenebrae Choir is a good start (although they do non-medieval music, too) as far as performers go. As far as composers: Josquin De Prez (although this might be cheating as he composed High Renaissance music) is great polyphony, and you can't go wrong with Hildegaard von Bingen for monophony. For multi-instruments (primarily non vocal) there is a pretty good album on Apple Music: the Last of the Great Troubadors by Martin Best Medieval Ensemble that rocks ... in 14th century terms ; )

And honestly thanks for asking! Too many times we give games away and there is no interaction - no community - and in strange times like these it is nice to just talk like normal people. May I ask: what is your native language? I enjoy all types of music but have a soft spot for world music, or at least music from cultures that are not my own!