Disarm and civilize the police but keep their SWAT units as a separate department that only backs up police when requested.
This would throwing a lot less people in jail and having police that live in the community. But hey, this is just wishful imagination, politicians and police union would commit sedition if anything like this happened.
That can be done in a reasonable amount of time.
Cops in LA are also very highly paid especially in benefits and overtime. Part of the reason why they are so short staffed is that it is cheaper to pay a cop well into the 6 figures in over time and pay for one retirement pension then it is to hire two regular time cops and pay two pensions. I don't know how you fix this issue beyond enforcing stricter criminal punishment against bad cops and start actually busting heads instead of slapping wrists.
That would indicate a leadership problem. Regular people just won't stay around when everyone from the top down is bent, even if the salary is outrageous.