Well, my post got deleted because the links I found aren’t allowed. But basically, yes, they sell a device on Amazon that seems to work just fine. I linked to another reddit post by someone who tried it. But it’s from a year ago when cards were WAY more expensive. The adapter sells for like $48 without memory. But I linked to the Sandisk 128GB CFExpressB card that sells for only $60. So while it works, for me the choice will be to just buy more cards and avoid having to do any work.

I don’t know if I’m understanding even after your explanation. Do you want to use an adapter that makes your CFExpressB card workable in the slot meant for an SD card? Or the other way around? Because if it’s the first, I’d think this would defeat the purpose of a CFExpressB card. Why not just get a quality reader for the card to take advantage of the max read speed?