Just to confirm, you are running the script below, correct?
curl -sSL https://repo.45drives.com/setup | sudo bash
I was able to run it successfully on a fresh install of proxmox 8.2 in a VM. However, I first had to apt install lsb_release which the script uses to check your version of Debian. Since 8.2 is built on Debian Bookworm, the script will ask if you want to use “focal”. Enter “Y” to move forward and it will setup the 45Drives repo.
Proxmox 8 and Debian Bookworm are technically not supported, but it does appear to work.