Nah, I have the same issue myself. If I arm the autobrake too early (like during descent/approach), often times just before landing it would have been off at some point. I’m also using FS2Crew and the F/O does have few controls in the aircraft. I’m not even sure if it’s the FBW A32NX, or FS2Crew or the hardware or MSFS control binding that’s causing the problem.
But I got used to having a workaround with it. Basically, on take off I leave my autobrake off because my F/O from FS2Crew will arm the MAX Autobrake by themselves, keeping it on until the landing gear is retracted and it will turn off automatically. On approach however, I usually keep my autobrake off until I command my F/O to deploy the landing gear. So once the landing gear is down, I use the quadrant addon dial to set autobrake 1-3 for Low/Medium. Then I call for landing checklist. At that point, the autobrake will keep being armed until touchdown and I press the manual brake.