To find out how much current you max in each motor you can use the odrive motor guide. Create a copy ('cause you can’t edit the original) enter your machine parameters at the bottom (pulley circumference, load mass, and bus voltage are the most important here) and then go to the motor’s “max current” column and keep lowering that until the motor no longer meets your benchmark for acceleration. Keep in mind that this isn’t perfectly accurate due to the fact that it won’t account for frictional losses or the weird kinematics of a CoreXY frame, but it should give you a good benchmark for what you need. Also keep in mind that exceeding the max current your power supply can provide will cause a sudden loss of torque, which might cause issues.
I feel like I also should state that the ODrive D5065 motors are probably overkill for you application. I’m building a CoreXY laser cutter and I’m using two Turningy SK 3536-1400 for my A and B motors and it looks like this (for refrence the machine frame is 75 cm wide and 50 cm deep). The motors I’m using have around a quarter of the power of the D5065 motors you named. Obviously this statement about overkill goes doubly for your extruder motor and possibly your Z motor as well.
If you have questions about some of the other design choices that I have made, or would like to know what components I’m using, feel free to send me a DM.