Haven't looked much at the code, but not using type annotations in a large python project in 2025 sounds a bit suspect.
As for tests, meh. Trying to test and catch errors in stateful processes is a losing cause, so I sort of get it, at least for a language like python. It's better to focus on making it fault tolerant. Let it crash and just restart the process. If it's a logical error, it should be easy to detect. No idea how fault tolerant piefed is designed to be though.
1000+ line files with no type hints doesn't sound all that great though, some people thrive in the chaos I suppose.
The feedback is a bit harsh though, and doesn't really inform the developers of why these issues are can be deal breakers for some.
Just out of curiosity, is there a particular reasoning for not using type hints?