Her deleting her twitter was inevitable in a way. All I see is her trying to escape the past, and she's been doing a few things in order to do so.
There a few examples that can back this idea up: first, she clearly has been trying to distance herself from peter and the coffin name. She removed the coffin name from her youtube and her twitter. She also deleted every single video from her youtube channel. And likewise, peter removed all videos featuring "his wife" from his channel. I also remember once browsing her twitter replies a few months ago (no screenshots so you'll have to believe me), and there was a few replies about peter starting to date another girl very soon after they separated, while she stayed a while before seeing other people(now has a boyfriend). So apparently, ash and peter do not seem to be on as friendly terms as claimed when they announced their separation. There was also that situation that happened in october, where she temporarily deactivated her twitter before coming back the next day, and then later claimed in her replies that, and I'm paraphrasing, 'her heart was irreversibly shattered recently bla bla bla' (also no screenshot to back it up so may be completely misremembering), so something clearly happened there in her life, may or may not be peter related(she released a picture of herself crying during that time span, and it was genuine).
Recently she acknowledged the existence of a subreddit dedicated to cataloging her pictures and discussing her. Also peter is well aware of this very thread, so we can assume that ash must also know of it's existence. So she clearly knows that there are people watching her every move and more or less cataloging them.
Theory time: when she deleted her twitter, she had around 145k followers, and we can safely assume that most of them are blissfully unaware of her 'backstory' per say. If we keep in mind that twitter is a shithole where anyone can get canceled for anything, you could see how someone could easily try and take her down. Most of her followers only know her as an attractive woman who shitposts on twitter, no more no less. The way I see it, she wanted to publicly distance herself from peter, while leading a more private life, and having such a large audience that could learn about her story was too much, and she decided to retreat to a small private account. She wants attention, but to her body(not getting into why), and not to her story and 'infamy' in some circles that could be largely expanded at any moment., and she wouldn't want to deal with that, and she also wants to keep the details of her life more private.
But hey, that's just an anon's theory.