Smoother return for Betaflight GPS Rescue in 4.5

This is some code I'm working on to smooth out the pitch blips in GPS Rescue of Betaflight 4.4.
Two independent PT3 filters, with user-adjustment. During the descent phase, where tighter control is required, the filter cutoffs are made more aggressive as the quad gets closer to home, increasing precision. This allows a smooth return. Some shaking on descent is inevitable.
Also I am making the disarm threshold on landing to be user-configurable and removed a bit of code that may have helped trigger early disarms.
Finally, there is an improvement in the climb phase, resulting in much less overshoot, by using a kind of velocity factor iTerm Relax, so that during the climb phase there is no iTerm accumulation.