TWRP - Backup Failed with Error Code 255 - CreateTarFork () - Samsung Galaxy S20+ Ultra

I have a fresh Nov/Dec updated ROM Build for my Samsung Galaxy S20+ (SM-G986B). Since it's a fresh clean ROM with all necessary apps and the performance of my phone is seamless, I want to create a backup for SYSTEM, BOOT, and DATA Partitions. The problem is when I try to back up these 3 partitions, TWRP keeps throwing the ERROR 255 - CreateTarFork() > and this is especially linked to my Data Partition Backup phase. Also, when it's starting to BACKUP, a long list of PERMISSION/ACCESS DENIED messages flood the screen. I am copy-pasting a couple of lines in order to relay more accurate info. I would also upload the LOG file and link it here. BTW, I haven't installed any Shelter App thing and I don't seem to have any other user folder other than the default "0" folder name.

I:digest_filename: /external_sd/TWRP/BACKUPS/Galaxy_S20/2023-12-30--03-14-17_TP1A220624014G986BXXSIHWKD/boot.emmc.win.md5
 * Digest Created.
I:Partition Backup time: 48
Backing up Recovery...
I:Reading '/dev/block/sda14', writing '/external_sd/TWRP/BACKUPS/Galaxy_S20/2023-12-30--03-14-17_TP1A220624014G986BXXSIHWKD/recovery.emmc.win'
I:TWFunc::Set_Brightness: Setting brightness control to 5
I:TWFunc::Set_Brightness: Setting brightness control to 0
I:Restored default metadata for /external_sd/TWRP/BACKUPS/Galaxy_S20/2023-12-30--03-14-17_TP1A220624014G986BXXSIHWKD/recovery.emmc.win
 * Generating digest...
I:MD5 Digest: 695136a16c032b39f631f630e383f6db  recovery.emmc.win
I:digest_filename: /external_sd/TWRP/BACKUPS/Galaxy_S20/2023-12-30--03-14-17_TP1A220624014G986BXXSIHWKD/recovery.emmc.win.md5
 * Digest Created.
I:Partition Backup time: 28
Backing up Data (excl. storage)...
Backups of Data do not include any files in internal storage such as pictures or downloads.
Error opening: '/data/bootchart' (Permission denied)
I:Error in Generate_TarList!
Error creating backup.
I:InfoManager saving '/external_sd/TWRP/BACKUPS/Galaxy_S20/2023-12-30--03-14-17_TP1A220624014G986BXXSIHWKD/data.info'
createTarFork() process ended with ERROR: 255
Backup Failed. Cleaning Backup Folder.

The link is here to the Recovery.log file. Recovery.log