I have 2 rings, a grill & an oven on the boat & sometimes have to swop pans around. I have 4 rings & grill only on the van & do miss the oven sometimes. Pressure cookers & double trivet ovens help compensate for a shortage of rings or oven. We also have a microwave in the van for when we are on hook-up.
But a lot depends on your style of cooking, are you cooking for one or six? Are you a corned beef hash & peas fan or do you like loads of veg & fancy cooking? Or do you mostly eat out? 2 burner & grill will often be enough for an excellent grilled meat, mash & 2 veg meal.
Lots of boaters I know cook canned food by dropping the can in boiling water, so easy to use 2 cans in one larger pan. Need a little care opening it, but it won't get hot enough to explode unless you let the pan boil dry.
Only you know your needs, no point really asking us as we may well have very different requirements.
Oven is useful for reheating pre-prepared shepherds or fish pie, for keeping chips warm will heading from chippy to camping spot, for cheapo Fray Bentos pies, for full roasts, or even quickie roasts using a ready-cooked chicken. Pasta dishes & sausage casseroles are lovely on a cold winter's evening.