Mac Mini M2 does not recognize my external SSD when restarting

I have a 2 TB SSD installed in a Satechi hub connected via Thunderbolt to a Mac Mini M2 computer. When restarting the external drive is not recognized. It is recognized when starting the Mac after a complete shutdown. Why? I am new to Mac. I want to use the external drive as my data storage drive where I will keep photos, music and files. Using a Seagate NAS as the intermediary between my old PC and the Mac.