I have been struggling to track down the source of this error FOREVER!!!!
It has been THE most vague error that I've EVER seen in nearly 40 years of programming!!!
Yes, I've seen WORSE lol
In the modern age of coding, this, however is the worst.
It took me weeks to track this down among 50 mods, countless games, countless hours to this mod. lol It is not your fault that the coding system is this vague. lol
Anyway, somewhere in your code, and yes, I WILL try to help you find it [I'm not THAT cruel]
is a misbalanced parenthesis. Your mod is amazing! It truly is. It's truly a work of art. I know that you have a team behind you helping you. They deserve praise too.

I started a clean install of Civ VI, a simple game of the game with just this mod. Poof, Database.log has this error in it.

Every time that I've had a game with this mod in it, it's present.
Every time that I've had a game without this mod in it, it's not present.

Any other conditions seem to be irrelevant.

Anyway, I'm going to proceed with narrowing down the search.
Wish me luck on my deep dive! :D