1) Beckman is comparable to Shanks according to his Bivre Card and volume 4 billion literally asks “is he admiral level??” about Beckman so it’s a question Oda wants you to be thinking.
2) Shanks’ commanders are the strongest. This has basically been stated and is frankly pretty obvious.
You put 1 + 2 together. Beckman is admiral level, Roo is a little below Beckman, Yassop is a little below Roo, it looks super obvious that he’s definitely stronger than guys like Queen.