I will surely disappoint many, but anything related to the system is very far from my cup of tea. Not that the subject does not interest me, but I very much prefer to focus on pure development tasks (which is very much felt in my spectrum of skills).
It is nevertheless important to know how to manage at least (most of the time it is just a question of good will). In France we have the excellent youtube channel of Xavki which talks about a lot of subjects around various OS, Docker, etc… Moreover, as far as I'm concerned, I'm not particularly a big fan of everything related with the frequent war between OSes... As a monitoring solution developer, I have a duty to set foot on the different existing solutions, which means that I have to experience different things (to already have a little experience in low-level binding on the different OS, I can guarantee you that there are always good things and problems on each system).
Caution
⛔ I say it often in this document but never lock yourself in an ideological bubble.
⬅️ 🔬 Monitoring: Others | ➡️ 💻 System: Scripting: Shell, Bash & Powershell