I think something to always keep in mind is that you're idolising these people, obsessing over something that you know deep down is a fantasy. I would encourage you to keep that knowledge at the front of your mind instead - that yes, your brain may be going a million miles per minute, but it is all ultimately a self-woven illusion. It's because you don't know these people super well that you're able to weave these illusions, so remember that you're basing those illusions on ignorance and not reality (because, as you wrote, those illusions do shatter when they do something in real life that reveals who they actually are).

My other advice for you is, are you someone who is a little shy socially, especially around people whom you admire from far away? My experience is that many people like that will create ideals in their head to avoid genuine emotional intimacy, often because they're afraid of getting hurt. In situations like that, I think it's actually good to just get out there and interact with people more so you're frequently confronted with the reality of who people are rather than what they act like inside your head when you're on your own.