In the proxmox UI select the following steps:

Check for the Disk to add:

lsblk -o +MODEL,SERIAL,WWN

Example results:

With this we can identify the ID of the disk since it won't have any partition assigned then we can run:

sudo lsblk |awk 'NR==1{print $0" DEVICE-ID(S)"}NR>1{dev=$1;printf $0" ";system("find /dev/disk/by-id -lname \"*"dev"\" -printf \" %p\"");print "";}'|grep -v -E 'part|lvm'

This means we can finally run the command to add the disk:

qm set 100 -sata4 /dev/disk/by-id/ata-WDC_WD40EFAX-68JH4N1_WD-WXXXXXXXXXXXXX

Reboot the machine and we can now use the new disk inside the machine