The stove burner (at least the "big" one if there are different sizes) should be plenty hot enough to brown meat in a frypan. If you have a three burner stovetop, with two back burners and one central front burner, sometimes the front burner is higher output than the back ones, even if the burner structure itself is identical.
You could have a regulator problem, or a problem with the stove itself. My RV stove has a separate secondary regulator (that could, at least in theory, break down) and there are the usual possibilities of a clogged orifice, etc. that cause gas appliance problems.