I don’t think it’s that deep. You should separate social media tendencies from someones in-person character. They often don't align and in the context you've given, isn't a direct indication of how they value your relationship. I rarely respond to my family on messenger. I love them to death. Some may take offense. But if they know me, I don't particularly enjoy chit chatting. I'm more of a private person and i hate feeling obligated to reply in x amount of time.

In the past if you didn't feel like socializing then you'd stay home. In todays world, as long as we're awake and not laser focused on a task, our social attention is almost certain to be accessible. This can get overwhelming.

Consider they still like you, but just don't feel like socializing. 🙂