What would you recommend that is not NixOS or a Bash script and can be used agnostic of distro?

This is not correct as pass uses GPG, and you can do symmetric encryption with it, it is just a different parameter in the command.

You can use a different password per file, or the same one

I use qtpass as a GUI for pass

Can I use it fully offline?

Yes, it is fully offline, you can back it up by any mean you could any other file, and it should be fine as the files are encrypted (should store the keys separated), can be a USB, an external drive, another computer in your LAN, a git repo, nextcloud, syncthing.

How do I back it up to USB drive?

You copy and paste the files

What does the day-to-day operation of Pass compared to Keepass look like?

As I said I use qtpass as a GUI so, open qtpass, search for the specific password file, double click, put the password for my gpg key and then the password I need is stored in clipboard for 30sec (this is customizable or can be disabled) and I paste it where I need it.

If I need to store a new password, just use the add password button, and input the data, it is that simple.

I’m going to mention Ansible as I haven’t seen it mentioned, and it can be used to locally manage a reproducible build.

It has already been mentioned, but as a minimum to replicate your system you need two things:

• Transfer/copy your entire /home directory as there is where the majority of the configuration files of your system pertaining the software you use (there could be configs you could need on /etc and on /usr/local or other dir), that is why it is recommended to partition your disk on installation of your distro, so the /home directory is already separated, as if you reinstall in the same machine you don’t lose any configuration in addition to your personal documents/pictures/etc
• Have a way to automatically install a list of programs/apps/drivers/libraries, and that is what something like a bash script, Ansible, nixOs, etc. could help you with.

The truth is that using any of the tools in the second point requires learning a bunch, so if your skill level is still not there, there is some work to do to get there.

adding Quillpad, as another alternative

QR is just image to text, most QR reading apps I have used, show you the QR content before going to the website (or let you disable opening the link directly) so you should be able to check the URL or content and see if the link is legit or not.

But let’s be honest most people don’t know or don’t even bother and that’s the real problem.

I use my old laptop as a server, and so far no issues with leaving it on 24/7

For me personally, when you reach a level where you can think, and communicate in the non-native language (without doing mental translations back and forth) with enough ease and speed, no mater the topic at hand (meaning that even if you don’t know a technical or specific word you can make yourself understood), and even if you make grammatical mistakes or have an accent, the point of the conversation is not lost between participants, then you can consider yourself fluent enough on said language.

My native tongue is Spanish (could you tell if I didn’t mention it?), but I have consumed so much content throughout (and yes I did check how to spell throughout) my life only in English and practiced enough doing conversations both writing and speaking (even with an accent) on the internet that I can communicate with ease and be understood.

I have visited the United States a handful of times for around a month for vacations with family, so I can say that I had to communicate with native people outside the internet now, but I haven’t had any formal education except a few very basic English courses in high school.