The unfriending and actively ignoring f2f are very decisive and deliberate, I can understand a slow fade in extreme situations but as others have said this speaks of someone scorned rather than a gradual but deliberated fade.
I'm ghosting someone at the moment and it is cowardly I admit, the things above are not though they're very obvious.
I think you need to take a really close look. I have gotten to the end of my tether with a particular friend, I didn't want any drama just not for her to figure so much in my life and therefore have the power to upset me. She has though become unusually persistent and not wanting to a) have a big to-do b) get back into being friends c) pretend everything was fine I ghosted her, I feel terrible as it goes against a lot of my values, but I've had so much going on I don't have the capacity mental or physical for the ensuing volcano, we are part of a larger group and have been for nearly 20 yrs and whilst we are spread all over the globe and rarely see each other together regardless of a pandemic, we are essentially still friends. So here ghosting.
What has she done, well she's always had a chip on her shoulder, v jelous.not much has changed despite fantastic career, house kids and marriage. But she was awful to me for yrs, sly digs and passive-aggressive, but confirmed to me by another friend in the circle who got so sick of her and told me, she then took a step back herself for a while. This was a long time ago and whilst she's better at concealing now it's still there. She's incredibly judgemental, of us all really her thing is with me about having periods of being a SAHM, I just dont have the kind of role where I can have a small child and work and my DH doesn't have the role where he is able to support me to do to. It is what it is. She hates this and having just handed in my notice at the beginning of the year her disdain was obvious.
She also blows v hot and cold with me - so it's a bit rich that she's accusing me of ghosting. She'll not return messages for wks/months on end, she'll hold events and not invite me (she didn't invite me to the babyshower for her first, as she wanted to keep it 'tight and local' managed to invite the other two friends from the group who are in the UK and her SIL who lives 100 miles away tho.
She'll visit one of the other friends from the group who I used to live within 50 mins off (friend's DP's family lives nearby) but won't invite me, leading other friend to feel very awkward, apparently, she'll literally txt other friend a few hours before saying I'm in town and coming round, whenever other friend has suggested inviting me she says oh it's very short notice, let's just keep it small etc. I'll often just find out via social media and other friend will awkwardley txt to explain. I then spend hours trying to analyse what I've done wrong and why she doesn't want me to be invited, tying myself in knots.
I don't live there now but was visiting just before Xmas and sent her a message saying might be a long shot but if you're in XX town I'm home this week and would love to see you, heard 0 back then see a social media post of her out with her SIL and her friends then out with another mutual friend the day after, so she was in town and staying in town. Got a message back 5 days after my initial one saying "yeah I was over but back now. How are you, looking forward to Xmas?" I spent the following two weeks when I should have been getting excited for Xmas with my DCs feeling low and snapping at them because I was constantly worrying about what I'd done to upset when the answer was nothing, nothing at all, I don't know why she does it, perhaps punishing me for the reasons why she is jealous, I have no idea. Then when I got the message re work after Xmas, I was like no, nah. I don't want to continue with this. I've had several messages since asking me what she's done and why I am ghosting her. So she clearly does not know. So to that end, I think you really need to analyse and definitely seek a third party opinion.