Flashing the latest LineageOS Nightly works fine - both with and without Mind the Gapps add-on. However, once I sideload NetHunter on top (Yes, I've completed the setup wizard before flashing NetHunter), I see the beautiful Kali Logo, but then it reboots twice, the second time, it reboots into recovery. I've tried sooo many things to correct the problem, that I don't even remember all of them. I'll try to list a few of the things that I do remember:

I've tried installing Magisk Manager and having it download the Magisk zip file, and then installing that file from TWRP. This results in an unbootable system - knocks me back into recovery.

Reinstalling The Stock ROM directly from the OnePlus site: Gives me an error that this file is only for oneplus1 devices, but my model is an "A0001". I find this very odd. I extracted the zip file, and found and patched the model check. I then repacked with the zip comand-line app, and flashed my patched version. I successfully reapplied the Stock ROM this way. However, after flashing LineageOS nightly, it goes back to model "A0001" again. Very bizarre!

What can be done here?