Xposed (Magisk Installed) Fixer for LOS 14.1 [Magisk Module]
I know the OP says they won't support any bug reports or help requests with Xposed involved, but since DarkExistence is no longer actively developing this ROM anymore (btw, this ROM is still great for breathing life into this aging machine), here's a Magisk module to fix Xposed not working!
Background: I decided to dust off my Galaxy Tab S and re-install LOS on it. For such an old machine, it works great with this ROM. Still very happy to use it for watching Media and misc BS'ing around. But for some reason, Xposed wouldn't install properly whether direct flashing or installing via Magisk (currently on 20201020, vanilla build). Xposed Installer (using topjohnwu's special build for Magisk) would report framework was installed but not running. Upon checking the logs and doing a little bit of digging, I found that it turns out it fails to copy a few files, so I created this Magisk module to fill in the gaps, and it immediately worked afterwards with no errors in the logs at all. I literally only wanted Xposed on this device to run GravityBox (for now), and it's been smooth and stable so far (making sure not toggling any conflicting settings - basically using it just for the advanced reboot menu, locking certain QS tiles while device is locked, signal cluster data traffic activity, shortcuts for tapping on the clock, and a few other odds and ends).
So if anybody is still out there who uses this ROM, or anyone who may stumble upon it in the future, and wants to install and use Xposed, here is my Magisk Module to fix the Xposed installation. First install the Xposed Framework module from Magisk Manager's online catalog (use the correct one - "Xposed Framework, v90-beta3"), and also install the correct Xposed Installer APK linked in the module's info/about window. Then install my module in Magisk Manager:
https://www.androidfilehost.com/?fid=10763459528675572059
On my device, the only missing files were xposed.prop, XposedBridge.jar, and app_process32_xposed, and all my module does is place those files where they belong in /system/. If anybody ends up using this, please let me know if it works (or if it was even necessary for you in the first place).