It's not all you. 2017 was the first time they made the change to stop "bunt cheese" online.
Of course, since they have to ability to impact things for specific modes...but I digress.
In any case, there's only so much you can do because it is actually a part of the hitting engine. Some things you can do:
-Release the triangle button with good timing. The player will still bunt at the ball and sometimes this deadens the ball more.
-Don't use influence to bunt. If you're playing Directional hitting, don't use influence to bunt except for the really good bunters. I'm guessing (key word) that when the attempted to push/pull the ball on a bunt fails, you get a rocket bunt.
-Remember it doesn't have to be perfect. Even some of the hard bunts can still move the runners along. A lot of times, the 3B will just go to first, even if it bunted rather hard towards him. The 1B will often go to the 2B covering or tag the batter-runner unless he's dead sure he can try to turn the DP. If the CPU is rocket bunting at you, you can follow similar rules or just go to 1B every time. It's a "house rule" and not ideal, but we can only do so much.
Slider solutions? Contact MIGHT help. Contact helps you succeed at all things hitting. So unless you need offense in general or willing to tweak other things to bring your production back where you want it, seems risky/lots of possible side effects.
Lowering Control as the other option, especially on Directional, but carries the same risks, perhaps even stronger.
Timing might help. This could help with the "release triangle with good timing" approach and it has fewer side effects in general.
Foul Frequency is a two-edge sword to bunting. This governs the "gray area" situations to hitting where the game decides "did he adjust to that ball his PCI isn't touching?" "Did he make contact at all on that really early/late swing?" This leaves the best, or at least decent, results more likely to be in play, which makes the better quality balls in play, while the weaker, bad, barely-got-the-end-of-the-bat-on-a-stitch-of-that-change-up go foul.
How does that relate to bunting? A lot of bunters probably enter this "gray area" a lot (especially now). Bunting itself is actually trying to
use the gray area to barely touch the ball, really. You're trying to intentionally get "bad" contact but put it in play so they get you but no one else out. Higher foul frequency might push more of those would be good bunts foul. Lower might kept them in play, but also make some of the really really bad bunts stay in play too (pop up bunts, for example, instead of going behind the catcher for a foul, they might pop up to 1B/3B charging or the catcher right near the plate for outs). Lower will also create more outright misses, which can be just as bad.
I think the bunts where you're playing pepper with the 1B instead of rolling a sacrifice out there are the game giving you decent contact in play instead of bad contact in play, which of course is a
failure for bunting.
But there's no easy solutions because it's hard to say if any of the slider solutions work, work consistently, work across skill levels and other settings, or are worth the side effects to the other 95% of hitting even if they worked consistently. Meanwhile the other mechanical solutions might get thwarted by the game engine just as much and it's hard to explain or show what "good timing on releasing the triangle button is".
But...that's pretty much where we are. Hope something in here helps.