If you really want to know linux you can install linux from scratch. Gentoo’s less work than lfs but will still likely teach you more about how linux works than Arch.
If you have your important data regularly backed up and things become unmaintainable, or break, just reinstall. The level of expertise and knowledge required to keep an install running like clockwork indefinitely will likely depend upon the complexity of the setup.
Might be worth trying out an Arch install in a VM to get an idea of the nuts and bolts.