Don’t use drugs to solve a problem like this. You’ll just build a tolerance and solve nothing.

Look into strength training as others suggested. Start with bodyweight exercises before moving on to weights. It’ll take a while though as you’ll need to experiment to find what works, and ofc exercise isn’t an overnight thing.

Maybe also consult a physical therapist.

And if all of that is too much, running isn’t the only effective cardio exercise. Cycling, swimming and less obvious/weird ones like slideboard mountain climbers, which should all be easier on the knees