I Accidentally Worldbuilt My Emotional Baggage. Should I Play or GM It Myself?

Context: Yes, I'm in therapy, and I am continuing other inner work. I'm not doing just this as my only tool for growth.

I've been worldbuilding for a campaign off and on for two years without much intention or hope to run it as a campaign, just as occasional fun. I recently picked it up again after doing a lot of work on myself. I realized pretty quickly that I had projected a lot of my internal issues into the world, especially the main conflict. This was pretty intense for me to realize.

After discussing it with a very close friend, we think it might be therapeutic for me to play in the campaign with a group. I'd hand it off to him soon, and he'd fill in the major gaps unrelated to my internal conflict. We'd find a group, and I'd spin up a character to play through. I'm pretty good at not metagaming, especially in a group context. We think both my individual player experience and the group experience of seeing the other players play through the conflict would be useful.

A few questions:

Is this common? As in, has anyone else realized they were using worldbuilding therapeutically, intentionally or unintentionally?

Do you think that playing through the campaign would be beneficial? Is it a good idea? Does anyone have experience doing so? Are there alternative ways for working through this that might be better, like GMing the campaign myself or a duet campaign with my friend GMing?

If my friend runs the campaign, any tips for him?

If we do this, should I tell the other players? I don't anticipate crying or anything, but I might have realizations about myself while playing.

Thank you.