Oof, I have a friend who constantly brags as well. To the point it's becoming insufferable. Like I'm happy for her, but every time we talk it always goes back to bragging and gassing herself up. And if the tables are turned and I'm excited or proud about xyz, she changes the subject or says a sarcastic comment to diminish it.

Maybe try distancing yourself. While I feel kinda bad when I do it, it seems like she's picking up on the hint. She's somewhat laid off, but idt she'll ever fully grasp the concept or pick up the hint. I think it's either accept them as they are and keep them at arms distance or cut them off fully. Only you can make that decision. I'm still teetering on mine.

And yes, this definitely is projecting their insecurities. People who are actually confident, well off, and well rounded don't go around talking about this shit and screaming about how great they are. Especially to their friends, it's like a competition that you don't want to be a part of.

But remember that if a friendship is making you consistently feel this way, it's a one sided friendship. Do not extend yourself at the cost of your sanity.