Welcome!
If you think the biggest challenge is going to be the terminal then how about a fun little game that will make you more familiar. It is a quite basic game that focuses on some of the commands that are used frequently in Linux.
I assume you already know the package/update commands of course.
https://overthewire.org/wargames/bandit/
I gotta say, with all the nonsense about using ai to analyze notepad and every PC is now a copilot ai PC, this feels like the year of Linux. I made the switch myself to Arch(hyprland) and personally discovered how much I love tiling Windows managers.
In case you're not aware, btrfs is amazing. I run snapshots on my days every hour. This works for my personal data and protects me if an update goes sideways.
And finally, I'm unsure about Mint, but on Arch, flatpak has been amazing for installing software. It installs as a tenant of your PC with limited privileges.
Also, since you mentioned steam, you may wish to look at gamescope in order to utilize the full steam deck ui.