Locked out - Changing PIN via TWRP recovery when disk is already decrypted

I have a rather unusual scenario for which I need your help. I am running an OP9 Pro with Nameless ROM A13 and Microsoft Intune forced me to set a 8-digit PIN. After the last update however, Nameless started to automatically decrypt (FBE) after entering 4 digits after booting even though I need to enter 8 digits, which is probably a bug. When going into TWRP recovery, the decryption with the 8 digit code works just fine, so I backed up my data in case a reset is needed. However I am wondering if there is any other way via ADB to change the PIN back from 8 to 4 digits. When in

shell

, it says

:/ # locksettings clear -- old XXXXXXXX XXXX

/system/bin/sh: locksettings: inaccessible or not found

Maybe I'm missing something here. Would appreciate your help. Thanks Edit: Would it be sensible to try to dirty flash another ROM without said "bug" over this? Edit 2: This circumstance actually prevents me from using my phone, as it automatically tries to unlock after entering 4 digits (even though 8 are needed) and therefore fails to unlock. By decryption in TRWP I knew that the 8 digit PIN is still correct and in place.