I do agree with what you're saying. BUT, the big question we need to ask is 'are they good enough NOW'. If the answer is no, then the type of club we are, we shouldn't be settling, that's the difference between being a Real Madrid or an Arsenal IMO. Maffeo would be the highest rated right back, because he's the ONLY senior right back, it doesn't make him good enough.
I don't know the answer to that question. I'm sure Guardiola does, and I trust his judgement. If we think they can progress to the point where they are good enough, but they feel they need first team football, then unfortunately we should let them go.
I just think Pep would have played one of them v Everton if he rated them, instead he's shown that he'll be more flexible with the formations rather then the names on the team sheet.