What do I do?
Almost everything is lost!
I thought I was in /run/media/somewhere.
It stopped at /dev/, but lots of stuff at /home is gone too. ;_;.
At least the cloud files are still there, but lots of directories are gone.
/bin is gone.
What I was trying to accomplish
My goal was to have stepmania working on a smaller computer than a mini-ITX,
because of constant wi-fi issues and why not go smaller?
My OS of choice: manjaro, but I was also going to try out raspbian and see how that fares
Also, I really preferred an external SSD card
as I've had bad experiences with the longetivity of SD cards lasting only a year.
Because RPi4 cannot yet boot from external storage,
one needs to install an OS on both the SD card as well as the external storage
and then copy some files to /boot on the SD card.
What happened instead
I was installing a new manjaro OS using manjaro-arm-installer,
multiple times because I wanted to test it on a flash-drive first and see if it worked.
Also, I was installing raspbian too to see if that worked better/worse.
After testing on flash-drives I bought an external SSD card.
I mounted it, but for some reason demounted it again and used manjaro-arm-installer.
This time I overlooked the fact that I was creating the OS to my own harddisk until it was too late.
Having noticed I had just tried installing ARM on my non-ARM computer, I searched for the changes made in /boot and got really confused.
Things looked normal. All the old files were still there.
"Perhaps I did install it on my external harddisk after all?" I thought
I also noticed that the external harddisk was remounted on thunar.
I already had installed raspbian on the SSD card before,
so perhaps I should clean it first this time around.
Besides, I don't know anymore if raspbian or an unfinished manjaro is installed on it anymore.
So when I went there, noticed that there were ARM files in ./boot,
I then decided to open terminal and delete all the files on it's root folder too so I would have a clean empty external harddrive again.
I was NOT in the root folder of my external harddisk.
I was in the root folder of my internal harddisk.
And by the time I realized it, /sbin, /bin were already gone and my encrypted partition corrupted.
It's probably better to buy a tinkerboard S and use eMMC or just use what I already have, an Asrock J4205 board.
Also, should have made backups.
I would have gone back just to be on the safe side the moment I noticed I accidentally was installing manjaro-ARM architecture on my manjaro-amd64 computer.