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Based on a true story
(sh.itjust.works)
Turns out the status quo of Linux memory management somehow works pretty damn okay, nobody seems to really know why, and nobody cares.
No, you absolutely don't need to care at all about the memory management when using Linux. This rabbit hole is really only relevant when you want to work on the Linux kernel or do some really low-level programming.
I would say the most obscure thing that is useful to know for running Linux is drive partitioning, but modern installers give you a lot of handrails in this process.