I literally googled “Steam Deck Plus” because I read it wrong and immediately wanted to know about whatever new Steam Deck Valve was selling.

Personally I've never heard of Stream Deck and can't stop seeing "Steam Deck".

Also subjective, but Steam Machine sounds corny.

I think they called it Steam Deck to avoid confusion with their previous Steam Machines.

I have to believe Valve has sold more units / has more brand recognition

Very true. I own both yet even I'm confused all the time.