Pep barely beat Inter while managing an country-owned investment fund with unlimited wealth and fraudulent sponsorships.
Some of the absolute best players in the world, even on the bench. Mou got Roma, a club with financial issues and FFP restrictions, to a Europa League final. Pep manages a club with unlimited wealth and financial fraud on top of that.
I do agree that Pep is probably the best manager in the world, but he can't hold a candle to some of Mou's achievements because Pep only manages extremely dominant clubs filled with absolute top tier players (Barca, Bayern) or a literal pay to win 'club' with unlimited wealth (City), whereas Mourinho actually challenges himself.
Do I think Mou's football is more enjoyable to watch? Absolutely not lol, no one would argue that. But Mou's achievements in the CL (Porto, Inter) are far beyond what Pep has or will ever achieve. The reason I tend to agree that Pep is a better manager overall is that he has a very visible transformative effect on his players, particularly the ones that aren't world class. You look at how Akanji has changed, or Nathan Ake, the lesser players in the squad.
You don't really see that with Mou, he's more pragmatic and his style doesn't really have a clear identity.
As far as his achievements go though, I don't think there's any real debate that Mou's achievements in Europe are forever beyond anything Pep has or will achieve.