If they are vinyl foil wrapped, paint may not adhere well.
When (if?) business returns to normal, you can buy spare kitchen doors in standard sizes and hundreds of finishes quite easily. They are made in a few large factories and sold to kitchen companies but there are various outlets on Ebay.
Ends-of-range and clearance stocks can be very good value. I equipped mine by buying up all remaining stock from a warehouse (but I had been looking out for a long time).
The cabinets are just rectangular boxes of laminated chipboard in standard sizes and a couple of qualities.
The standard European kitchen cabinet hinge fits just about any make. Though the size of base door and hinge position standard altered slightly around 20 years ago, if you measure your door size accurately (to the mm) and the distance from centre of hinge to top/bottom of door, they will know what standard you have.
If you want to give it a try you could buy one door and learn how it's done. An experienced person might take thirty seconds per door, you can take longer.
Or you can pay someone to supply and fit. Kitchen companies have quite high margins.