Go to AK for gear and ifrit hard. Both can be done with gear not obtained in endgame. AK has some nice upgrades.
As someone pointed out, AK and Ifrit will do you fine. You're about where you should be.
AK is designed for fresh-ish 50s, despite what most people think, so you can run it easily, especially because you have a i55 weapon.
Thanks guys. I was afraid of being locked to do Castrum 24/7...