That is an interesting thread.
9 ball, what you should try: Keep your hard tip and take another, “sharper” dome/curvature radius on it. CETERIS PARIBUS: The smaller this dome radius, the more you can go off center and the more you can transfer spin/effet (but maximum limit is dome radius = ferrule radius; you can’t go further and you can’t go on with ellipsis, that physically will not work).
Drawback: A “sharper” calotte radius is more unforgiving (I don't mean miscueing, I mean spinning the ball "accidental", when you don't want or need it).
So maybe a change from quarter to nickel or to dime (or even smaller) could help, ASSUMED your stroke is reliable and sure. As stated: Much depends on your stroke technique!
Changing tip shape is in any way worth a try and not very time consuming or effortful, assumed you (or your cue maintenance guy) have the right, adjustable tip shaping tools.
My English (I mean the language and the effet ;-); still learnng and working on both) is not the best, but I hope you understand or can at least feel/intuit what I mean.
My 2 Zlotys
Olaf