Tried setting disksleep to 20 but it it didn't work for me. Still getting the “Disk Not Ejected Properly Eject ‘Backup’ before disconnecting or turning it off”. messages even when the computer is awake. I tried reformatting the SSD and running First Aid on it but nothing seems to help.
2022 Mac Mini + Satechi Type C Stand and Hub with SSD + Western Digital 2TB SSD.