The way it seems to work, when selecting export for Unreal,  Accurig exports the UE4 skeleton setup - is there a way to set it to use UE5 skeleton setup?
They are quite different, UE5 has been out for quite a while and it would be handy for the Accurig to provide me with the option to select which UE skeleton I want.

Is such a setup possible?  

No it wont export for UE5 skeleton, but it really needs to be updated to do so, and CC4 of course. but knowing Reallusion, this probably wont happen until CC5.