Retail Win7 product key or ShowKeyPlus product key to install Win11?

I installed Win10 on my self-built PC using the product key from my retail copy of Win7.
I now want to dismantle the Win10 PC and use the power supply and SSDs for a new DIY Win11 PC.

I ran ShowKeyPlus on the Win10 PC. The "Installed Key" is different from the Win7 product key I used.
Searching tenforums, I found a post that said: "When you install win10 with a win7 key, it changes the key to a win10 key".

So when I'm ready to install a downloaded win11 media creation on the new PC, I'll first deactivate win10 on the old PC.
Then I'll take the PS from the old PC and install it on the new PC plus a new 256 GB SSD for win11 and installed programs only.
I'll install the data SSDs from the old win10 PC after I get win11 working on the new DIY PC.

But when I install win11 on the new DIY PC, which product key should I use to activate win11? The retail win7 key or the ShowKeyPlus key?