Debian is a stable distro, so software versions will remain pretty much the same over the life cycle. This is good if stability (software not changing out from under you) is desired, but if you want to take advantage of new features as they are added to whatever software you’re running, it’s less beneficial. So, if you’re going to run debian as a desktop os, I would recommend switching your apt sources to point to the unstable branch: sid switching your apt sources to point to testing (see below).
You’ll probably see a lot of older tutorials and stackoverflow posts that use apt-get, which predates apt, instead of apt as the package manager. apt is the recommended frontend; apt-get will work, but apt will have a nicer user experience.
Also, on the topic of apt, there are three ways to run updates that you’ll probably see online; this stackexchange post provides a pretty good explanation of the differences between them.
General linux advice that I think is worth sharing
Man pages are pretty helpful once you know how to navigate them. Some tips regarding that:
You mentioned that you tried manjaro, so I think you probably already know what man is, but just in case: man is the command that you use to pull up manual pages for basically everything.
You can search through the man database for a keyword with the apropos or man -k commands. For example, apropos video pulls up a list of all the man pages that have the word video in their names or descriptions.
You might notice when running the above command that there are numbers in parentheses after the manual names. This is because the manuals are broken out into 9 sections based on the types of pages they contain. You can put the section number before the name to specify which section to pull up the manual from. So, if you had two manuals named foo in sections 1 and 3, to pull up the one for section 3 you would use the command: man 3 foo. If you want to read more, man has it’s own manual page, which you can pull up with man man.
You can search for text in man with / and ?. / performs a forward search and ? performs a backwards search. You can jump forward to the next result in the search with n or back to the previous result with p.
The bottom of man pages will have a ‘see also’ section, which lists related commands. Some man pages will also have an examples section.
Another good place to look for documentation is the arch wiki. A lot of the information on there translates to other distros fairly well, and it’s got huge amounts of well written information. If you use duckduckgo, the bang for it is !aw.
The shell is pretty intimidating for a lot of new users. While it’s not strictly necessary for most things, I do think that you’ll have a smoother linux experience if you become at least a little bit comfortable using it. Here is a bash guide aimed at beginners.
Finishing Thoughts
Looking back at what I’ve written, I realize that I have dumped a lot of information on you. So I think the best piece of advice that I can offer is this: Becoming comfortable with linux (or any new operating system) takes time and can feel overwhelming. Don’t feel pressured to understand everything immediately and don’t be afraid to go slow; Rome wasn’t built in a day.
I’ve been running linux as a daily driver for 6 or 7 years now, and I run debian on my servers, so if you have any questions now or in the future, I am happy to try to answer them.