Linux

unshare -nc followed by a command will run that program without network access. Very useful if you're running trash in Wine

First thing I'd do is ditch the GUI file manager: get comfortable with cd, ls, mv, rm, etc.

After that, maybe start with basic text manipulation, like grep, awk, sort, uniq, etc. This ties in nicely with IO redirection, which is essential for a "CLI based workflow." Get comfortable with pipes and file redirection, it's extremely powerful!

Writing shell scripts is another super useful exercise: any time you find yourself running the same set of commands multiple times, think about making it a shell script. You may end up with some really useful little custom tools that way.

Dotfiles. They let you customize your command line experience. There are loads of examples on GitHub. Reading through the comments on dotfiles that other people share help you learn about all the things that can be done. Customize your shell with aliases, functions, history behavior, syntax highlighting, etc.

I'm a Mac user who tinkers with Linux off and on, but I absolutely love that you're learning about the world of Linux. Welcome to the party!

https://github.com/topics/dotfiles

Shameless plug of some of my own custom tooling: https://github.com/fantismo/dotfiles

KDE is your friend in the trenches, Kubuntu > Ubuntu 100%

Regardless of whatever distro, definitely keep all your stuff backed up on an external drive. I had to "restart" my install a few times to get the hang of things. Yet I still keep all my info on an Vegacrypt encrypted external just in case to this day.

I do not know what sort of power management software exists by default on Ubuntu, but for laptop use I would strongly recommend getting a power management package like TLP to configure power profile settings for your laptop when on battery and on charge. It can greatly improve battery performance. Some alternatives like auto-cpufreq and powertop exist, but I have tried all 3 and found that TLP worked the best for me.

Here's a good reference: https://linuxjourney.com/

Remember to play. There are multiple terminal emulators, window managers, shells, all the things! Try 'em out. When installing stuff to test via distro package, keep note of which dependencies were dragged in so you can get rid if all of them, not just the thing you wanted to test. Also keep a list of what you tested and later got rid of (and why) so you avoid testing it again.

If you ever ssh into other machines to do stuff, learn the minimum of vi (classic w/no arrow keys, not vim) and bash. Servers "always" have those (though FreeBSD also has tcsh).

I think the two "major tips" that I can give you are simply

1- Package manager is your best friend.

2- Figure out the "know-hows" of Linux (i.e who "is responsible" for the video card, who deals with the cpu, how do i configure my sound card, how do i configure my video card, etc.).

Master those two tips and you can call yourself an average linux user.

Welcome fellow Linux beginner.

What are some really important basic commands I can use to start branching out into Terminal command structures

Since I refuse to touch the Terminal like my life depends on it, I can't help you with this 😅

And if Cinnamon has shortfalls or weaknesses that I may run into eventually, what are some good alternative distros that I could leapfrog to eventually?

I'm a little biased, so take it with a grain of salt: Cinnamon's biggest flaw is the lack of support for the Wayland protocol. It's still running with x11. As far as I have read about it, X11 has several big security flaws, and it slowly dies a long, quiet death. As far as I know, the Linux Mint devs (makers of Cinnamon) haven't even started on Wayland support. A good alternative would be the KDE Plasma Desktop. It's insanely customizable, and the default look comes very close to classic Windows. As a KDE Distro, I would recommend KDE Neon since it's based on Ubuntu too.

Set up btrfs and timeshift. You never know when you need that big undo button.

Most distros are good enough without much tweaking. in terms of commands...some more advanced stuff...

start poking around proc to see what linux gives you, without needing a program to get it!

Probably already mentioned in other comments, buy it can't be stressed enough: Backups !

Part of learning to use Linux is breaking it. You will make mistakes that will bork your computer. You can either spend hours to try to fix it, or you can wipe everything clean, reinstall, restore from your latest backup, and be done like nothing happend in no time. (Maybe you want to go the hard way for learning, but it's always more relaxing to know you also have the easy option at your disposal)

Ubuntu comes with Timeshift, make use of it. Also plan to make backups to external storage or NAS, in case things go real bad.

@Classy Give a try trade-free linux distro TROMjaro.

Honestly, youtube "basic bash tutorial" and watch/follow along with a video or two. Helped me a bunch.

Just a tip for running wine. Wine "helpfully" add file associations to wine programs, which is super annoying. Imagine opening a text file, and instead of opening it in gedit when you click it in your file manager, it opens the files in notepad instead.

If you want to clear these unhelpful file associations, check out the "4.3 How do I clean the Open With List?" section on wine faq here: https://wiki.winehq.org/FAQ#How_do_I_clean_the_Open_With_List.3F

Books, books, books! O'Reilly publishing is your best friend. Search engines are next. And finally, Youtube.