Auto mode not holding bank long enough

I am trying to tune up a flying wing better and the main issue is when e wing turns it does not hold the bank angle long enough for tight turns. If I hold the sticks to the side while in the turn it banks nicely to he 60 degree angle and holds. This results in overshoots of 40m required when assisting the turns in auto mode and if I don’t use the sticks to assist the overshoot is 80m. Note the plane still hits it’s 60 degree bank angle but does not hold it long enough. What is the best way to fix this?

Have a look at plane.ardupilot.com/wiki/navigation-tuning/ if you haven’t already.

Changing NAVL1_PERIOD and NAVL1_DAMPING can tighten up on the nav quite a bit.