Help removing 2-piece crank arm

This feels really simple, so what am I missing?

Taking of the crank arm of my son's bike to service the bottom bracket and the drive side doesn't want to come out. Do I just need to bang (the non-drive side) harder with my mallet? Am I missing something else?

I don't have a plastic mallet. Could it be that my rubber mallet (like this one) just isn't giving enough force? I don't want to damage the crank!

Removed non-drive crank arm

Drive-side doesn't have any extracting bolt (that I can see)

Do I simply hit harder here?

Thanks for any help!