And then a few more any time you actually want to use it.
And then double it each time you have to decipher the existing one
Just don't use regex unless there is really no other way, and when you absolutely have to - frankly, that's one of the ultra rare occasions I recommend using the AI.
Regular expressions in general, and automata theory, sure you should know about that. But a specific extended regex language like here? That's like saying you're shit at coding if you can't do <insert arbitrary programming language here>.
Yeah, I've found myself wasting quite a lot of time thinking of the 'perfect regex' for task X only to realise that I could have avoided doing so by simply taking a different approach.