Your question lacks depth and you need to research this topic much more.

You don't buy on brand per se. The term gas range means many things to many people. There are gas cooktops. There are gas stoves. There are gas double oven stoves. There are gas double convection ovens. There are La Cornue Château Series gas stoves which cost more than $100,000.

As a form factor, a gas cooktop and oven are kid simple BIFL items intrinsically. A $50 yard sale item will function just as long as a $13,000 Wolf stove, the kicker is we don't know any of your use case items which are many: budget, oven amount/size/form factor, size, griddle need, grill need, downdraft vent need, color, and many other things.

So for anyone to give you a brand name will be a disservice without you asking a more specific question.