Kahn removed all his previous skills, weapons, armor and battle modes just to start with a clean slate as he activated Asura Mode after a long time. This was a form where he could mix and utilize the most effective and prominent bloodlines and their particular skills absorbed to this day. And now, a newly transformed and upgraded version of the Asura Mode appeared in front of everyone on this battlefield.
Was there a way to kill Axel using different combinations and techniques at this point?
There could be a way but the Hero of Fire had already received immunity against hundreds of such ways to die and even one common factor was enough to waste their whole efforts just because Kahn acted overconfident. Hence, he decided to use only new and different ways their crew hadn't used before because the clock was ticking and they couldn't risk waiting till any reinforcements from the Church arrived.