Looks like your minimum and maximum pulse width is not adjusted yet. Please check in the forum how to set them properly. But that is also no explanation for the drop outs during breaking.
I did adjust them, at some point I put it on 0,9 and 1,9. The strange thing after leaving it at that setting was when the remote was set to “off” the motor would go full power forward 
Im not sure what you mean by drop outs during breaking, I wasnt breaking during the test? I also noticed that its much harder to spin the motor when the remote is on and Im not adding speed…
You have to enable the display check box. Then move the throttle completely forward and backward and check the valuesin the box with the label Pulsewidth (ms). Set the lowest as minimum and the highest as maximum. Then write the settings and check afterwards what % the display shows. When the throttle is in idle it should be at 50%. If it is not you have to adjust the minimum and maximum. So that it is at 50% when in idle. Always when you make changes write the settings first and then check the percentage of the display box. Sounds complicated but give yourself some time and try to understand how it works.
Does this chart work in my case? I calculated cutoff start 21 and cutoff end 19,8. With these settings the skateboard is now really overpowered (id actually like to downpower it), but also it manages to get motor detection unlike with 33/30 setting.
Is this safe for the circuit to leave it at this?
I really need some info on battery cut-off start/end.
Are they 33/30 respectively for any motor/battery combination or can this number vary?