I mentioned this before, but just for the benefit of anyone not seeing it, the MUR160 600V 1Amp fast diode works perfectly as a replacement of all these ZS diodes, and they are just $0.38 a piece at Mouser, present stock >100K.

https://www.mouser.com/ProductDetail/ON-Semiconductor/MUR160RLG?qs=sGAEpiMZZMtbRapU8LlZD9Yt6EMzPspSTOq4%2FRfw2Ns%3D