The sense of ungroundedness sine waves over time afaict. The old strategies for connection had untenable foundations (e.g. tacit shared metaphysical assumptions), so you'll need to learn new ones. The Charisma Myth and NVC are good for bootstrapping some of the skills. Motivation in the new regime can't arise because you don't have even the proto-skills necessary to get a rewarding feedback loop going yet.

Can't speak for anyone else, and I don't know what my counterfactual selves feel like. https://www.lesswrong.com/posts/6NvbSwuSAooQxxf7f/beware-of-other-optimizing - I don't know if you and I are similar in ways that matter on this topic. In fact, I don't know what mental features are important for how to optimize on this topic. Anyway, this is not advice, simply a framing that works for me. For me, I believe it's worth it. The tunnel widens a lot, and has LOTS of interesting features in it, but it does not end - there is a fairly fundamental truth underlying that loneliness, and I don't know of any acceptable ways for me to deny or forget that truth (to myself). I've become hyper-aware of the complexity and variance in humanity, and in myself moment-to-moment and year to year. This makes me quite able to have deep connections with many people, EVEN WHILE understanding that they model the universe differently than I on many dimensions. We can't have and don't need agreement on everything, or even on ontologically fundamental topics. We can agree that sitting around a campfire talking about our human experiences is desirable, and that's enough. With other groups, I can explore moral philosophy without a realism assumption, even if I don't particularly want to hang out with them on less intellectual topics.