3 weeks post full acl/mcl tears with meniscus damage as well. how long should i wait before surgery? swelling has subsided lots and im very strict with doing my physio as well as extra leg work. how long should this keep me in bad pain post-surgery?

You should see an orthopedic surgeon sooner than later to get the ball rolling. With both ACL and MCL tears, your knee is left unstable and will result in significant joint destruction without the stability from excessive unintended mobility. Initially the swelling would have caused stability that will quickly be lost with the resolution of the swelling.

Most people would schedule surgery once your range of motion is back to normal. Most people have pain for 1 to 3 weeks after surgery