If you want to learn how operating systems work, you need very, very little computer science and math.

A book such as “UNIX Internals” (https://www.amazon.com/UNIX-Internals-Frontiers-Uresh-Vahali...) should be a good start (just quickly browsed it. It seems it’s 100% free of formulas, supporting my claim you need very little math)

Newer books probably exist (this book is almost 25 years old), but I don’t think that matters much. The details have changed (schedulers and allocators can get a lot more convoluted on modern systems with non uniform CPUs, hyper threading, etc., for example) and there’s some new stuff, for example in virtualization/hypervisors, but the core concepts haven’t changed, and that’s what learning how operating systems work book should start with.

And yes, it only discusses UNIXes, so it ignores Windows, VMS and the like, but you have to start somewhere, and that book isn’t a bad start.