How did you raise AC who want to live close to you?
I am in tech and come from a family situation similar to yours. I do not want to live next to my parents (mother and her partner) who live in DC and I generally do not enjoy spending time with them. Here are the three reasons why, which I'd anticipate apply just the same to you as to them:
1. You are divorced. You've already identified a root cause. You've divorced. There's no way around it. Divorce makes family awkward and brings someone new into their lives.
2. You live in a swamp. You've identified another root cause. For many people, DC isn't a great place to live. It's an inhospitable swamp in the summer, in a larger swamp of country clubbing lawyers, lobbyists, and politicians. Since your children are in tech, odds are they've grown used to the casual and more energetic environment of the west coast tech hubs like Seattle and SF. You couldn't pay me to live in DC after settling in either of those cities.
3. You are a ball anxiety. The fact that you are posting about this situation on DCUM betrays your attitude toward life and children: anxious. Anxious parents just aren't fun to be around, sorry. The anxiety is palpable and suffocates you during family reunions.