My transistor used in a transistor amplifier does not get turned off with PWM based input
In the wiring diagram that you're showing, you won't see any PWM regulation as you're applying directly 24.5V to the motor when the transistor is off. You're basically shorting the power supply if you turn the FET on. Below you can see the typical low side switching configuration.



Image source: https://www.gammon.com.au/motors