That is not your problem. Your problem is your laser is expecting a positive going PWM pulse and all of your fan outputs, as Dan says, provide the PWM by chopping up the ground because they all employ N channel FETs. You will continue in a world of hurt until you manage to rectify this basic problem. Either use a direct PWM output from the MCU (seeing as the SKR v2 does not have a dedicated output for laser PWM your best options are either PE6 (currently assigned to RGB) or PE5 (currently assigned to servos),
other than that you will be directly soldering onto R93/R94 junction to obtain the fan2 PWM signal before it gets to the Fan2 mosfet (not recommended)
…or invert the fan output from the FAN2 socket J24 using an opto-isolator or transistor inverter. See Issues getting laser configured properly - #17 by dart1280
An oscilloscope will be of great benefit checking for a proper PWM signal
Your 10v isn’t right. the FAN2 socket J24 has VBB on pin 2, this should be the same as VMOT , this should be the same voltage as DCIN. Check the voltage at F2, if that is 12V suspect a faulty Q2 or U5
