I was in this position where I broke up with my bf of 3 years because as far as I could tell I wouldn't be able to see him until at least 2022. We broke up and cried and both didn't want to let go. I still wanted him and him me. We decided to attempt for one last lifeline and apply for a travel exemption for me to leave Australia which would affect my uni study duration.

It was approved and that saved us.

If I was you I would make it clear if you want to be friends or if you don't want to community with her. Maybe you both want to be free from the stress of not being together but still care enough about each other to leave the possibility of another chance later. But if that is the case you need to respect her decision to move on, date other guys, get heartbroken by them and come crying to you, tell you about all these fun things that she is doing HAPPILY WITHOUT YOU. And she needs to be in the position to do the same.

Personally I was not ok with that because I was still in love with him, it just got too hard.

So in the end it's up to you. But don't ghost her. Explain why you don't want to communicate with her. She will be hurt but you broke up and she likely will accept it with grace and understanding.

Neither of you wants to hurt the other.