In my experience, far and away the best tool for drilling sheet metal, diecast boxes and acrylic sheet is a 'step drill' also known as a 'cone drill'. They start their own pilot hole, don't snatch or grab, and are easy to use in a pillar drill (not a hand held electric drill). You just continue drilling one step at a time till you get to the desired sized hole. No dramas. EG. This one drills in thirteen steps from 5mm to 35mm:
https://www.amazon.co.uk/gp/offer-li...&condition=new
You can get more expensive ones, but as they tend not to get used too often, a cheap one is good enough for most requirements.
Hope that helps.