Code reading techniques

Background info: I'm a software dev with around 10 years of experience. I understand my own code (I mean even the ones I wrote years ago) and I also navigate through framework code quite OK (e.g. Spring Framework) but I really struggle understanding most of the enterprise projects I work on. I don't know if it's because of me, but they all seem really tangled, unorganized and sometimes I can't even tell what the class I'm looking at meant to do.

Can you recommend any resources (books, videos, articles) or techniques to get better at code reading and project comprehension?

I've read the book Software Reading Techniques but it was crap imho.

Thanks all, Happy Holidays!