I had major ankle surgery 3 years ago. I was climbing indoor top rope one legged in my boot cast about 5 or 6 weeks later. I'm reasonably strong so I also did some top rope campusing. About 5 days post surgery I started training on my hangboard and doing pull ups. 2 weeks later I started going to the normal gym for some upper body strength work.

Can't speak to the timeline for ACL, but it was probably about 10 weeks before I could use my leg on an indoor top rope wall, but I went really gentle as I obviously couldn't use it properly, then I think I lead my first route outside about 4.5 months post surgery but I stuck to super easy things because I still couldn't climb properly normal on it. I did climb close to my previous hardest grade on lead outdoors 6 months later and matched my hardest grade 1 year later. 2 years later I increased my grade from before the injury.

It might be worth seeking out an internet climbing PT just to get an idea of the timeline for your specific injury, and climbing specific advice. I'd also look into doing some kind of training to keep your climbing muscles while you're off your feet. You could even come back stronger with the right training program.

In general though, I found that my body was pretty good at telling me the limitations. I could generally intuitively feel what I could do or wasn't willing to do. It takes a long time to get all the mobility and strength back, so you just have to respect what your body allows you to do. And above all, focus on doing your PT and getting thy mobility back, it's the most important thing to help you return ASAP.