Isn't that the point though? If there is a player out there who they think represents both the quality and is available, then you'd expect that they'll sign him. If they don't then it suggests that there isn't one that they're sure will give them more than what they already have.
For the record, don't get me wrong I'd absolutely love them to sign a right back. But I don't want them adding players to the squad who aren't going to represent the sort of quality we've bought in Ait Nour, Reijnders, and Marmoush. If that means having to wait until next summer then I trust Pep can get much more out of Lewis and Nunes. The reality is they both played in an incredibly unstable team and unstable defence last season. If the whole team's performances improve, then I'd expect Lewis and Nunes's performances to improve too.