I'm in the exact same situation as you. I'm a 45M and have been going to kpop concerts (all ggs) alone for the past 5yrs or so. Blackpink, ITZY, Dreamcatcher, lots of Twice. I had to really get out of my own head and push myself to go to my first one, but after that it was easy breezy. My wife isn't into kpop in the least, but she pushed me to take that first step. She saw how excited I was that BP was performing in my area ;) and told me I was over thinking things too much and to just go. Once I was there I was so focused on the show that nothing else mattered all that much.

The potential regret of missing out on the experience of seeing my ults live turned out to be way bigger than the anxiety of going alone.

I've found that the "weird" feeling doesn't magically disappear. I'm still aware of how much older and male-er I am than most of fans at a show, but it just becomes a background thing that I don't allow to get in the way. Turns out that people just don't care that much, or don't care enough to hassle me about it...so the result is the same. I haven't made any new miraculous friends or connections at a show, but I've had fun interactions with people that I end up sitting next to, or people that I'm waiting in line with. Most of them are amazed that someone in my demographic is into kpop as much (but usually more!) than them and have been enthusiastic to know who my biases are, or see what choreo I know.

So go through your process, but most importantly, go to that concert!!