I think of all the people out there Ace is one of the most difficult to actually power scale or he is the lord of ties. In Alabasta he is shown to tie with Smoker (at that point in the story the readers would not know how strong Ace or Smoker might actually be), he just commented that their devil fruits cancel each other or some shit and then escaped etc. Then we learn that he and Jinbe fought for 5 days, again showing an equal power level. We see him having a high-extreme diff fight with BB but the last attack of Ace and BB is shown to be equal. He is also shown to have tied with Aokiji in a clash at Marineford but then loses to Akainu because of elemental inferiority. He also ties with Yamato. Now idk what is the chronological sequence of the fights but this is what seems to be most likely.
1. Ace fights Yamato (probably did before joining WBP about 4 years ago), Yamato would be 24 at that time and she probably has most of her powers.
2. Ace fights Jinbe (maybe we can swap this with 1 depending on the timeline, Ace joined WBP right after this I think). Jinbe most likely was also near or at his strongest.
3. Ace fights Somker (clash or whatever but Smoker is a captain). Ace is chasing after BB.
4. Ace fights BB (some back and forth, final attacks visually shown equal). This BB gave Shanks the scar (when did this happen).
5. Ace fights Aokiji (just a clash of elemental attacks).
So we have Ace who tied with Yamato, someone who is anywhere between Flying Six to YC1+ level. Then this same Ace ties with Jinbe who is at best a YC3. Then we have the clash with Smoker who is a captain and below Flying Six. Then we have BB who is at least YC level, maybe even higher since he managed to scar Shanks. Then we have an Admiral. So Ace can range from anywhere between Captain and Flying Six to YC1 level?
1. Ace fights Yamato (probably did before joining WBP about 4 years ago), Yamato would be 24 at that time and she probably has most of her powers.
2. Ace fights Jinbe (maybe we can swap this with 1 depending on the timeline, Ace joined WBP right after this I think). Jinbe most likely was also near or at his strongest.
3. Ace fights Somker (clash or whatever but Smoker is a captain). Ace is chasing after BB.
4. Ace fights BB (some back and forth, final attacks visually shown equal). This BB gave Shanks the scar (when did this happen).
5. Ace fights Aokiji (just a clash of elemental attacks).
So we have Ace who tied with Yamato, someone who is anywhere between Flying Six to YC1+ level. Then this same Ace ties with Jinbe who is at best a YC3. Then we have the clash with Smoker who is a captain and below Flying Six. Then we have BB who is at least YC level, maybe even higher since he managed to scar Shanks. Then we have an Admiral. So Ace can range from anywhere between Captain and Flying Six to YC1 level?