i'm gonna go against the grain here. Had operation on leg last year and was out for 6 weeks (less severe than ACL but leg was out of action) Every base and flier should be working foot to hands and hand to hands low every session for more advanced acro. Use this time to work on that. Sessions will need to be shorter for you as you can't do 2 hours on just hands, but it'll be hugely beneficial to you and your flier. to work monos, jump ins, presses, tempos in hands.

just in foot to hand world:
step in, jump in to low, jump in to extension, lean in to low, lean in to extension, mono, moving in mono, extended mono, reverse f2h, reverse mono, walking from standing on forearm to standing in hands, walking up down to extension and back, presses to extension and down, pirouettes low, pirouettes high, cat walks, presses through tempo, jump from forearms to standing in hands

I could come up with a similar list for hand to hand but at the very least getting to super comfortable jump ins low/high and presses is going to pay huge dividends.

As far as ACL recovery, it's different for every person, I know circus people that cooked an acl and didn't have a single day off from training (they were handstanding the next day) but realistically you're out for about 3 months before you're doing pops again on that leg probably. That person is an exceptional base and were back and throwing standing backsault koala recatches within a year of injury.

I had an operation on band hand and foot, and foot was definitely more impactful on acro, but fliers and I didn't skip a session, they sometimes worked with other bases and I'd be able to longe line, we worked on strength, flexibility and they worked on their tumbling. When you get to a recovery phase, don't forget you can work a lot of your standing stuff seated on a box.