How do you like your Rumble? Lots of people love em, so perhaps a larger model could be the ticket? What kind of sound are you going for?
Pre judging cabs by speaker size is a well worn myth. To say, “10’s do this, 12’s do that and 15’s do that other thing” is not only untrue, it could keep you away from a dream rig because you went in biased. It really depends on what sort of 10, 12, etc (there are many, all with different design goals) in what enclosure design. Keep an open mind and try as many different amps/cabs as you can. I’ve had this post gig conversation too many times...
(Them) “Man, I love your tone. What are you using?”
(Me) “Thanks! I’m running a sealed 18 with two soft dome mid drivers.”
(Them) “Really? You should try a (blah, blah), because the 12’s (or whatever) really have more of a (blah, blah)...”
(Me) “Umm, ok, but I thought you just said you love my tone?”
There a a ton of ways to get what you’re after and ultimately you’re the only judge of what that is for you. Take your time and have fun!
Where’s the fun in that?!

100% agree to do your homework and get the best rig you can afford, or you’ll just keep swapping out one piece of cheap crap for another and will have spent even more in the end.