With KDE riding high on OpenBSD - why not user that as the base for the EU standard OS?
TL;DR - KDE runs well on OpenBSD (See eg rsadowski's blog post here https://rsadowski.de/posts/2024-05-20-kde6-on-openbsd/), large chunks of the system is developed and maintained in Europe anyway, so why not use that instead?.
The project is formally headquartered in Canada, but in reality there are enough European developers (mainly German and French, but other nations represented) involved that I for one think that OpenBSD (https://www.openbsd.org) would be quite well suited as the basis for a general purpose standard operating system for European users.
I wrote a thing a few years back about hows and whys -- nicely edited and split into three chunks by APNIC at https://blog.apnic.net/2021/10/28/openbsd-part-1-how-it-all-started/ (part one of three) or the whole thing at my playground https://www.bsdly.net/~peter/what_every_it_person_needs_to_know_about_openbsd.html - the main points stand aft er four years, but I'm sure there are bits that could do with updating.
So enjoy! Discuss! :)