I've encountered this type of problem even while it was connected to the PC. Nobody else seems to have documented this. What happened to me was I tried booting into RCM, Windows detected the APX device indicating I was successful as well as the fact that my screen stayed black, but then almost immediately the APX device was no longer listed even though my screen was still black. What I did at this point was to simply retry entering RCM at which point Windows detected the APX device again and it stayed detected. The only other time I've seen this type of problem happen is with Windows 10 users but you were able to load the payload at least once so your operating system is working appropriately with the Switch. I don't have a jig myself so I don't know how fixed the wiring inside it is, but some people have reported a lot of failures even with jigs. I personally use a paperclip and while it may not work 100% of time, as well as being dangerous to the pins, it gets the job done.
This guide will give you the entire installation process from start to finish:
https://gbatemp.net/threads/switch-hacking-101-how-to-launch-the-homebrew-menu-on-4-x-5-x.504012/
The only step you will not follow is when it asks to download a payload called Hekate. You will immediately notice this when you see a 4.x and a 5.x but not a 1.x
https://github.com/Jan4V/hekate-ipl-50x/releases/tag/v1.0.0 This is the one you need to download for 1.x