Follow up on the previous thread https://www.dell.com/community/Optiplex-Desktops/9020-USFF-Mini-PCIe/m-p/7246712, I can confirm that 9020 USFF mini PCIe does support mSATA, even if it was only marked as "PCIE MINICARD" on the board.

I popped in a Samsung PM951 mSata card and it works great.  The card also has Dell PN 00Y6FC but I believe any mSATA card should work in this standard interface.  More photos next.