The key word is crammed. Insulation shoulder never be crammed. It's no longer insulation then. One of the deep flaws is having the vapor retarder toward the roof. That's fine in your area when the space insulated is air conditioned, bu in the this case we have to worry about the moisture load and source.
If the bays are crammed then you'll have to remove it all and start again.
You can buy baffles to keep the insulation away from the underside of the deck and maintain air flow.
If there's NO sign of mold on the insulation that can be reused. The batts can be split length wise so they're thinner.
There's no need to paint the plywood and 2x12's.
You could reuse the Insulfoam.
If the there's a craft paper or aluminum vapor retarder on the insulation -- it needs to be removed.
The sequence would be demo, dry framing, inspect for mold, clean with bleach, install venting, install venting baffles, install fiberglass insulation, install board insulation, install 4 mil poly vapor retarder, caulk any penetrations like wiring, install drywall, prime and paint drywall.
Reduce moisture load around garage especially where it's built into the hillside.
You could just remove it all and paint the framing. If the garage is attached to the house it will increase the air conditioning load with the it being hotter and the heating load with it being cooler.