New Dell Inspiron desktop with Windows 11 - that won't activate...what is going on?!

Just unboxed a brand-new Dell PC (I didn't alter anything or add hardware), plugged it in, created a local account (I only use a local account as I don't have or want a Microsoft account) and when I ran some Windows Updates I noticed that it wasn't activated. I clicked the ACTIVATE button in Settings but it errors:

"We can't activate Windows on this device because the product key was already used on another device."

with error code:

0xC004C008

I build new computers all the time from other manufacturers and have never experienced this. I thought I would give Dell a try but I am instantly regretting this decision! What is going on?

Thanks in advance for any help.