One of the biggest things that helped me was setting up virtual machines and installing different versions of Linux in them and just playing around. I found it super helpful because it makes you learn different things (for example you mentioned reading the Arch wiki which is a good resource, but not all of it will apply to Mint necessarily) and as an added bonus, it doesn’t matter if you break everything. You can just restore a backup, or better yet, reinstall from scratch so you get used to the process or better yet, keep breaking stuff until you come out the other side and get things working again!