I can second the recommendation of Robert Love's books on Linux (https://rlove.org/ https://rlove.org/) as well as "How Linux Works" by Brian Ward. I personally

I can second the recommendation of Robert Love's books on Linux (https://rlove.org/ https://rlove.org/) as well as "How Linux Works" by Brian Ward. I personally enjoyed "Linux Kernel Development" by Robert Love more than the former as it teaches you more about Kernel internals (IMHO). The drawback is that it's a bit outdated already (it's based on the 2.6 kernel) but on the other hand most things are still relevant as far as I know. Andrew Tanenbaum et. al.'s "Modern Operating Systems" is a good reference to learn about operating systems otherwise, independent of Linux.