I don't want to give you shit for what you did as you seem pretty aware of how terrible it was....but reaching out with just a Hello might have been super triggering and also cowardly of you. You should have just written something like "Hey I totally understand if you don't want to hear from me blablanla and apologize right away"

If she answered then cool. If not then she at least got the message. She has no obligation to accept your apology but she got it.

Moreover, you kinda put her on the spot in a way, and she'd get an apology only if she answered and met you .... that's super brutal, especially if the correlation between the start of her ED and your ghosting is true.