first go see mudah, carlist, fb marketplace to see how much your car is worth.
then check with mechanic and see if the amount to repair is worth your time. sometimes after repair can get your money worth.
or just fix any mechanical issues, cosmectics just leave it.

mytukar/carro and carsome cant really tipu, they're used car salesman as well, will check every nook and cranny before giving you a quote.

or you can sell as is under market value while letting the buyers know the existing issues.
the unethical route would be selling it as is and hoping the buyer don't know cars.