So, a few years back I installed AntiX-21 onto a 20+ year old onto an old WinXP laptop both as a fun project and to get some practice with Linux. It worked fine, and I mostly used the resurrected laptop to watch youtube videos and listen to podcasts, which was just a fun novelty to do on such an outdated machine. Obviously I couldn't do Youtube in a browser, but I could take URLs and watch videos with VLC in 360p.
At one point VLC video playback stopped working entirely and I could only do audio, I assume because of changes to Youtube. I tried using the AntiX Updater, but even after updates playback wasn't working. Looking at the version numbers of the updated versions of SMPlayer, VLC, etc I noticed they were still not the latest versions available.
I went to the repo manager and added a bunch of repos until I saw more up to date versions of VLC and other programs in the package manager, then used AntiX Updater again and said yes to the over 1,200 updates.
Things didn't go smoothly. The updates were constantly interrupted by errors but I kept restarting the update process until I had to log off for the night. When I logged back in the following day, the desktop I had been using was missing and I could no longer connect to the Internet because ConnMan was broken. I managed to connect to my Wifi with CENI and kept trying to get the rest of the updates done. I just couldn't get ConnMan to update no matter what so I rebooted the laptop again. This time the bootup process was filled with error messages and I could no longer log in at all. I'd enter my username and password and it'd just loop back to the login screen.
I'm pretty sure my AntiX install is bricked now. I assume I should try wiping the Linux partition and reinstall?
I just wanted the latest version of VLC 
Debian tells us that you should never add repositories to a Debian distro. It's the first rule on the Don't Break Debian page. "don't make a franken-debian" https://wiki.debian.org/DontBreakDebian
Third party repositories could have malware or be compiled incorrectly for your system.
Also 1200 package updates means that probably every package on your OS was replaced. Your computer reenacted the Ship of Theseus. There's probably no AntiX left in your system.
I'm currently in the process of formatting and re-installing AntiX with the Live USB I still had. I guess I should've taken the opportunity to upgrade to AntiX-23 while I was at it, but I can do that later.
Like I said though, the official repos didn't seem to have the most up-to-date versions of the media players I use