It really depends on what kind of "repair" you get done, and how you exercise afterwards and develop slowly movement again.
I had a partial meniscus resection. Started walking without crutches 3days after surgery, went into physiotherapy and exercised 5days after surgery and went back to BJJ 6weeks and 1day after surgery amd started rolling very easy immidiately.
A friend of mine got his meniscus "stiched" and it took way longer (3months no grappling, 6month no sparring)

A meniscus repair really takes time. I know 2 people that got theirs repaired, both came back to training and tore it again as they came back too soon. You really have to be 100% before coming back so patience. If you wanted to come back sooner, you should have just got a meniscectomy.

You can't load it for around 6 weeks post surgery. Then you can start conservative rehabilitation to get you back to jiu jitsu. Now you cannot put a time line on it. But a good rehab plan will have objecitve markers in place to guide the process. So make sure you get a good MSK rehabilitation clinician designing and implementing your programme of recovery.

Wrote about my experience on another thread. Tl;dr: Tore my bucket handle at the end of November 2024, had the floating piece removed mid December and resumed normal training 6 months later. Now almost 11 months later the knee feels quite good and has full ROM. Leg strength at the bottom end of ROM is still not quite 100%, but it's coming back fast.

I don't know any grapplers that have come back after meniscus repair and not tear it again. You can get it fully healed with lot of time and being careful, but most likely it will just break again once you resume hard training. IMO it's not worth it and it's better to get the floating piece removed.

For some months you could do selected techniques and "roll", starting from being mounted, just trying to avoid a submission (no advancing, nothing fancy, just defense - nothing that will force you to activate your leg). Just chill, let the leg rest and work on what can be worked on. If you are not sure if you can manage this, give it the resting time it needs. BJJ is for life (hopefully), so some months off the mat will not be an issue in the mid/long run. You could go to class and watch, also leaves a mark in your mind.

Overall, put health first...

Six months is a blip on the radar in a full Jiu Jitsu career.

According to your profile you are 17 years old and I know at that age 6 months seems like an eternity. It's not. You need to listen to your doctor and do what they say regardless of what a group of random strangers on the internet tell you.

Take your time, don't rush it. I'm in the middle of MCL/ACL reconstruction surgery. I have to keep checking myself, to not do too much.. for longevity go slow and steady.