jesus no! :ohnoes
If the paint is stuck to the car now, paint will stick on that paint later.
Wash the entire car. Spray on, and wipe off (one direction, flip rag, wipe… no circles, you are lifting the crap and wiping it off the panel) with panel cleaner and wax remover. get a gallon of it. Just washing it and taking media to the car will embed the wax and crap into the paint and screw your next color.
then get a DA and 600 the entire car dry. Tight spots use a grey scuffy pad dry.
ready for paint other then removing bumpers, trim, or masking its ready for base… sorta.
You can also use a “scuff and clean” paste in a water solution to grey scuffy the entire car AFTER DA, body work, feathering, etc… S&C has a slight grit and degreaser/cleaner agent in it.
CLEAN CLEAN CLEAN is the key.
Are you doing any body work? Any burn throughs to bare metal need a cover of self etching primer, then 320-600 feathered out into good base/clear original paint. Same with filler, gotta prime and feather the repair out. No need to reprime the entire car if your going whit to white. If there were a ton of primer spots or its an extreme color change, full sealer coat is recommended.
Thats the basic of it.