Thanks for your answer.You can try the boot-recovery script from the amonet folder to boot twrp. You can also follow the OPs whole unlock/unbrick procedere (with shorting) until you reach TWRP, then wipe system, format data, wipe cache, flash a clean stock rom.
The lineage rom for sloane isn't up-to-date and it's supposed to work with a locked bootloader because back then the unlock wasn't aviable...
Can you please send me a link to this?
For example I already tried this (amonet-sloane-v1.1 ) but couldn't start the script.
With these (amonet-sloane-v1.3.zip) the script could be started but there was always an errno errno 5 or an errno 19.