Admirals get more hated on.
And contrary to what many post here, it isn't some form of backlash against admiral agenda bois.
Yonko fans push massive agendas as well. In fact, the agendas pushed by Yonko fans at large was worse IMO, when takes like 1 yonko = 2 admirals or even 3 admirals were quite prevalent.
Though honestly, that is on Oda to an extend too because he made the narrative of admirals more subtle compared to Yonkos who get wanked often on screen. I also had Yonko mid-high diffing admiral when I was a casual, based on Marineford showings, and I never had any agenda against admirals ever. I changed my mind only after listening to narrative arguments of admirals in forums.
Admiral fans for the most part, were right in that admirals and Yonkos are in the same tier. Which we are increasingly seeing to be the reality. Truth IMO is that Yonkos "on average" are stronger than admirals, but the gap is still not high enough that they are a different tier.
Still, the higher levels of the "top tier" (i.e the ones the fandom generally considers "high top tier" or above) are usually just Yonko like pirates with advanced conqueror's haki - Rocks, Roger, WB, Kaido, Mihawk (real yonko of CG), Shanks, Rayleigh. Garp, Sengoku and maybe Akainu are really the only "admirals" at this highest level.
All that being said, Admirals get more hate simply because Yonkos have more fans, well since this is a manga about pirates.