I'm NT (I think) but I resonate with this. I have an online friend that I've known since about 2005; he's autistic, though neither of us knew that at the time (late diagnosis). Anyway, around 2014 or so, he just... disappeared. He was going through some nasty relatioship issues so I figured he needed time to get things sorted, or was maybe depressed (I have experience of that and I know the last thing I want to do when I'm depressed is talk to people). Anyway... in 2021, he messaged me again out of the blue, and we literaly did just pick up right where we left off, and its great. We immediately went back to chatting nearly every day, and still do. And he's now happily divorced.