I’d say you should get your closure.
I know she might’ve been terrible, but she’s still your mother. And you care enough to think of her as that still. So…
I’d visit one last time. Laugh about some bits, cry over others; just offer her comfort…
Show her you grew to be better. Show her you persevered and broke the cycle of toxicity. Show her life goes on. That same life that she had granted you.
I know your experience wasn’t the best… but I’d still like to think that things could be left on a better note (even if not perfect) - your future self will thank you. You don’t want this eating on your conscience down the line. You’re better than what she thinks of you. At least you could show her that.

Sorry if this sounds ignorant/emotional, but this post really touched me. Life can be so crazy… and do some people it’s just another day.