I need a budget robot vacuum around rm300, as a midweek part-time cleaner. I would consider spending rm500 if the robot vacuum is efficient enough to replace my weekly vacuuming routine, though I still need to clean other spots besides the floors as my house is very dusty. (3 BR apartment <1000sqft)

What feature should I look for?
Is mopping feature any good or should just focus on vacuuming?

My suggestion is to get a better one. Budget ones will struggle with obstacle avoidance.

Better to get one that can vacuum and mop. I have just gotten myself one recently. Why did I get it? Coz I don't have time to clean my house anymore and too poor to hire someone to clean. Hence, decided to spend a fortune just to get a robot.

So the one Im using is from roborock not too high end but sufficiently good for me. It avoids most of the obstacles, and keep my house clean. All I need to do is to set a schedule to clean the whole house, and change/add water 2 to 3 days once. My house is so clean now.

Don't skimp on it. Just spend a little more and you will get your money worth.