I am currently using 400 dpi on my mouse but based on other runs it seems that it is to slow to be able to move fast, any idea on the best dpi for speedrunning ball and axe???

Preference honestly. I use something like 1600 DPI but I really don't think it matters, just depends how much you want to move your mouse and how comfortable you are with a higher DPI

I have always used 400 dpi since I like slower, but I feel like I should use a faster dpi simply for speedrunning ball and axe, I'll try 1600 dpi so thank you ig