The fee isn't going to the receiver though if were talking about sender/receiver in a transaction it's going to miners. The amount being sent to the receiver is fully hidden. But yea if were talking about a purely privacy perspective the fee being exposed isn't ideal.

Not sure how there could be a fee market for blockspace without it being transparent though. Maybe there is some clever a way to do it but not that I know of. Transaction ordering would have to be a best effort of "first seen" or at random afaict.