Sounds like the shop working on this was guessing and was not a BCM to start with
I would require they give you back your BCM
For settings to come and go seems like some connection within the BCM they put in

Most cases a wiper delay problem is within the turn signal/light stalk on steering wheel has lots of contacts inside and some times
needs to open and clean them up

Replacing the fuse block sounds total bogus and since problem happens after they did that I would demand back that money also
and then find another shop that is pros in working on Corvettes