Hi TC3
I haven't read all your post(s), but I get the gist of it, and it sounds to me like you know what you're doing, and what the issues are/were. So I wouldn't be concerned.
I've been doing gigs for 5 decades now, mainly at a very amateur level, but with occasional more serious gigs thrown in, notably playing at a Pro Jazz Festival in 2003 and playing in the support band for US Blues Guitarist Buddy Whittington in 2010. For those 2 I was very nervous, but proud with what I'd achieved.
I've encountered all the issues you describe many times, and they are just a fact of life for gigging musicians. You'll never know when you're going to face them, and just when you think it's all going brilliantly something will go wrong. As you rightly say it's not important. You're doing it for fun. The worst thing that can realistically happen if you/your band does a bad gig is that you won't get invited back.....
I took up drums after I retired in 2020, and the years of experience on Piano/Keys enabled me to start using them in a band within a year, because I understood what would be important for anyone I was playing with. I'm a very very basic drummer, but I can keep good time and for a lot of Pop/Rock stuff that's all that's needed!
A little bit of nerves is a good thing. I still get those, but I don't worry about a little bit of nerves. If I make a mistake (and I do) I move on. Generally nobody ever knows.
The main thing is, hopefully, that you're having fun. If you're not, that's when you should start worrying!
Cheers