@2955732195, by default, Android is encrypting the device unless you specifically tell it not to. I don't know if it just encrypts the SD card or the system partition as well, but it's more than just the finger print lock. Older Android phones did not do this (by default) and it tends to lead to behaviors like what you are seeing.
For example, came from MSM Extended. When to migrate to LineageOS, I did a factory reset, flashed the FW, LineageOS then GAPPS. When I went to reboot, it brought me back to TWRP (same as you). I had to go into Advanced in TWRP and 'Format Data', which wiped my SD card (actually just user memory, but Android calls it the SD card). I then pulled the zip files back over via ADB, reflashed and I was up and running.
Is there any reason you are running AddonSU vs Magisk? Shouldn't you boot and run through the Android setup before flashing this anyways?
For example, came from MSM Extended. When to migrate to LineageOS, I did a factory reset, flashed the FW, LineageOS then GAPPS. When I went to reboot, it brought me back to TWRP (same as you). I had to go into Advanced in TWRP and 'Format Data', which wiped my SD card (actually just user memory, but Android calls it the SD card). I then pulled the zip files back over via ADB, reflashed and I was up and running.
Is there any reason you are running AddonSU vs Magisk? Shouldn't you boot and run through the Android setup before flashing this anyways?