Hook Grip vs Mixed Grip for Heavy Deadlifts

I am currently pulling around 200kg and my grip is starting to fail me. I have been using mixed grip but I am starting to worry about the risk of a biceps tear on the underhand side. I have heard that hook grip is the way to go for long term safety.

The problem is that hook grip is absolutely painful. I tried it for a few sets of five and I felt like my thumbs were going to explode. Is this something that you just get used to over time or am I doing something wrong? I am using plenty of chalk but the pressure is just intense.

Which grip do you prefer for your heavy deadlifts? If you use hook grip how long did it take for the pain to become manageable? I really want to avoid using straps as much as possible because I want to compete in sanctioned meets soon.