Premium Select is in name only. Delta feels they can get away with an inferior product with corporate booking prohibiting J, but W is allowable—why pricing is sometimes the same or +/- $100 for D1. Leisure travels are fooled by the name who have hoards of Skymiles to burn from being hooked on the cobranded credit card mouse wheel of spending to earn SM for an inflated redemption.

Last summer, July 2023, ATL-FCO stayed in PS as no D1 available using a GUC. Return was AMS-ATL on KLM with Z space available around 1 week prior to departure. I prefer to purchase MC on a KLM operated flight and set a ExpertFlyer alert when Z space opens up to then call in to apply the GUC.