I’ve always maintained that the Monster Trio is, indeed, a thing, but that it has no bearing on the three characters’ powerscaling overall. Obviously compared to the likes of Nami and Franky, Luffy, Sanji and Zoro stand head and shoulders above. With the addition of Jinbe, we now have 4 members who are significantly stronger than the rest, but this by no means implies that the four are equal or even close to each other in strength.
I see the M3 as being similar to the 7 Warlords. Are they stronger than the average pirate? Yes obviously with the exception of Buggy. Yet Mihawk is leagues above Moria and even Doflamingo, similar to how Oda separated the M3(4) in Wano by placing the strongest two on the roof.