I have diagnosed NPD (with ASPD sprinkled on top, I’m “malignant” as it were) and I’ve been dealing with it for a long time. I’m still dealing with it, though I can tell it’s gotten “better” in some respects. I also have quite a history of being deceitful and manipulative.
Generally, whether they have NPD or not, people have zero incentive to change what they’re doing if whatever they’re doing has benefits that outweigh any not so great consequences. In light of this my question becomes:
Why do you want to “get better”?
Knowing what exactly your motives are is important, otherwise you’ll just sabotage your own efforts (I’m speaking from experience here.)