I don’t have a specific RPG in mind.
I believe that you can have an open ended campaign with any RPG. I don’t think one would be restricting enough to not allow that. Up until now, I have used a few RPGs and none of them were that restricting.
My RPG of choice is D&D 5th edition. I chose that over the others I’ve tried because I just feel more experienced with it.
That’s my answer to today’s question. Tomorrow’s question is “Which RPG do you enjoy adapting the most?”. That’s an interesting question.
So until then, have fun!