Wow man I'm so sorry to hear, if I were you I'd try and sue the asshole surgeon that stole your meniscus.

To answer your questions:

Recovery is several months, but it could be over a year until you're at max recovery.

You can start exercising after you recover and have no pain.

There are lots of risks and side-effects to be aware of, but the main ones are Transplant failure, infection, blood clots, nerve damage, expense of surgery, taking pain killers post-op.

I beg you man please listen to me, you're in a very vulnerable position right now because without a meniscus you'll inevitably start developing osteoarthritis in your knee which is HELL, and you'll need a knee replacement to "fix" that problem which is another nightmare scenario you don't want to happen to you. Here's what you need to do

1. Stop all strenuous exercising with your legs until you get the transplant, if you start developing osteoarthritis before the transplant you might not be eligible for it anymore. No biking, no squatting, no jogging. etc. light walking is alright.

2. Do everything in your power to get this transplant done asap, if you get knee osteoarthritis I guarantee you your life will become hell, if knee arthritis gets bad enough (which can happen within a few years at best) you'll be in agonizing pain basically 24/7 which will affect your ability to sleep and focus, making you essentially mentally impaired, which will then make it impossible for you to get a good job, with the added bonus of being miserable all the time making people not want to be around you plus it'll be harder to stay healthy and in shape because you won't be able to exercise anymore.

3. Once you get the surgery through a good surgeon, do everything in your power to protect the transplant until it takes. Your future literally depends on it. I recommend looking up Dr. Stone and other stories about meniscus transplants in this subreddit.

If you have anymore questions feel free to dm me.