When you can write a busy beaver machine in the type system, LOC ceases to be a good indicator or how long something should take to typecheck, imo. If you're frustrated with your build, you should use the trace tools on the TS wiki[1] to track down what types are slow to check, so you can attribute the slowness to the appropriate library authors/yourself and decide for yourself if the speed/correctness tradeoff they've made is right for you.
[1]https://github.com/microsoft/TypeScript-wiki/blob/main/Perfo...