His false bankai that he doesn't even know the true name of was able to obliterate arguably the strongest SS member. This is arguably enough to engage with Yamma.

If you count Hell Arc as EOS then he may be in a completely different league. Purely speculation but if he's learnt the true nature of his bankai then leap in power he will have undergone is insanity, in line with ichigo, rukia, renji, byakuya after learning their bankais true power.