TWRP not mounting new decrypted block device after successful decryption

[knerlington]

• I am running an official build of TWRP, downloaded from https://twrp.me/Devices/
• I am running the latest version of TWRP
• I have read the FAQ (https://twrp.me/FAQ/)
• I have searched for my issue and it does not already exist

Device codename: Lilac
TWRP version: 3.6.1_9-0

WHAT STEPS WILL REPRODUCE THE PROBLEM?

Boot into TWRP
Decrypt /data using password
Decryption is successful
/data/media/0 is mounted on /sdcard which resides on partition sda66
Can't create an image of said partition without the encryption being there

WHAT IS THE EXPECTED RESULT?

Supposedly decrypting /data in TWRP should give a new block device (/dev/block/dm-0 for everyone else trying the same thing) that you can create a raw image from which no longer has the encryption. Need a decrypted image of it in order to possibly recover lost/deleted data with recovery software on PC.

WHAT HAPPENS INSTEAD?

Ends up with the /data/media being encrypted and unusable

ADDITIONAL INFORMATION

Using a XZ1 Compact with android 9