Humanius

I had the same experience with Spotify recently, but apparently they are Swedish.
There is low-key quite a few large European tech companies that are easily assumed to be American.

OP’s question is for “single board computers developed or produced in the EU or Europe” though

The Raspberry Pi foundation is headquartered in Cambridge, UK.

https://nl.m.wikipedia.org/wiki/Raspberry_Pi_Foundation

Not sure if you are looking for a Pi replacement specficially, but if your goal is only to buy European, the Raspberry Pi already has you covered