I'm sorry I don't have the answer to this.
I personally avoid pretty-much all social media (except for PC, of course.)
But, then, I'm old. So it really doesn't matter much in my case. I'm not on Facebook or Instagram or anything like that. I also don't often post my own threads here on PC either. And when I do I always feel a twinge of embarrassment later & wonder why I did it.
You asked about tips for how to overcome your fear of social media. My only thought would be to just dive in & do it... more-&-more. The more time you spend on it, the more comfortable you would (hopefully) become with it. I suppose if you really wanted to focus on this, you could develop some kind of a program where you reward yourself for accomplishing certain pre-set goals in terms of participating on social media. But that may be a bit more involved than you want to get.
Here's a link to an article, from PC's archives, that offers tips for moving out of fear & into your life. Perhaps some the suggestions in this article can be of help:
Moving Out of Fear and into Your Life