Isn't this a case where regex may be the worse choice?

or I could have an LLM do it in a few seconds, and it'll get 99.99% of the cases, missing maybe one case every hundred thousand...

Even if the LLM does things perfectly 100% of the time, how do you expect to maintain your skills if you offload all of your work onto a chatbot? What happens when you start offloading more and more until you're not actually doing anything except typing in prompts?

Lots of folks here create absurdly high expectations that most coders don’t meet. They are out there but they ain’t average. Getting it 80% correct with good human reviews to catch the trash and using it to figure out what’s breaking quickly vs tracking down logs has been great for our team. I laugh at some of the garbage it spits out and the dumb way you can see shit like, ‘I have to be honest I did zero testing’.

Frankly, your use case sounds like something has gone horribly wrong from the outset. If something needs several thousand regex patterns, then something is very very wrong, and there's zero chance you have a comprehensive solution as it stands. Either trying to use regex for a use case that some natively AI approach might actually be warranted for, or regex is being used poorly and each one is too limited, or some other approach entirely is warranted.

Yeah I'm not a fan of slop merchants and PRs the size of battleships but anyone solving merge conflicts by hand because they hate LLMs is being a tad masochistic in my opinion. I'm in two minds about how much coding itself ought to be automated, but I'm a strong advocate of automating the tedious donkey work we'd absolutely have got rid of years ago some other way if possible.

It's also good for avoiding tarpits, sometimes I literally don't want to learn something because it's too expensive relative to the value of retaining it. I would rather crawl over a mile of broken glass and hot coals than learn the detailed ins and outs of WSDL just to support a legacy feature which is firmly in the crosshairs of my deprecation gun, to use a totally neutral and not driven by personal bitterness example.