Advice wanted for great relationship... gone...

[Sanity Claws]

3. Sorry you are going through this

It is hard to figure out what exactly was going on in her heart and her mind.
She was interested in pursuing a relationship with you and by the time she got to the point of showing up at your house without anything happening, she gave up. She thought this is just too hard; I'm moving on to someone who can appreciate me.
She might also have thought that she shouldn't put so much effort in pursuing you now that she has another job, where she can meet new men, and that the pandemic is receding, she can meet new folks outside of work.

She may have already found that new man. Why else would she have said no telephone calls? IMO, she didn't want her new love interest hearing a call between you and her.

I don't think feeling like the adult in the relationship while she acts like a 15 year old is helpful. She has decided to move on. Some people totally ghost another at that point. She has instead minimized contact with you.

But the point is you want her back, whether as a friend or romantic interest. Stay in touch but only occasionally and only with upbeat messages.
Can you send her a gift to congratulate her on her new job? She gave you gifts.
Can you give a small party and invite her? Probably not while the pandemic is going on but you could say you would like to hold a party and have her come and invite her Mom too. You could make it sound like a fun thing to look forward to. You could ask for her ideas and have fun planning to celebrate all the good things in life -- the end of the pandemic, her new job, etc.