Have you tried booting into fastboot??? And then checking on fastboot devices??Unfortunately, i cant find lineage 16.0 anywhere, but i see there are people on reddit forums who were able to update their phones to 17.1 though twrp, so i'm thinking my issue is beyond that. I tried going back to twrp by installing it over adb(enabling adp though the lineage recovery, sending the command to go to fastboot, and then "fastboot flash recovery twrp-3.4.0-0-z2_plus.img", but it just says "waiting for devices". Prior to that i can see the device if i type "adb devices" in recovery mode)
I feel like the more i mess around with it, the worse i am. I'm struggling to get TWRP back on it now. Atleast from TWRP i could have probably placed a different rom on it.