Power level wise, all I got was that top tiers are not invincible(something I've always said) and there are strength in numbers. Let's take a look at what happens with restrictions and/or distractions.
Aokiji- got hit clean by Jozu and his lip bleed. Also got kicked clean by Marco and face brusied.
Akainu- Marco and Vista got clean hits on him and could hold him off.
Fujitora- G3 Luffy could bruise him
WB- fodder could hit him clean.
BM- Queen could crack her skull
Kaido- G3 Luffy sent him flying
All admirals were holding back in their battlles in order to not destory the place and Fuji+GB are no different. All it shows is that yonko and admirals can't fight multiple commanders without using all their power.