I’d have to be pretty sure that I can install Qubes-OS without any problem.
Then you should start from the community-recommended list as those are the only ones you can “be pretty sure that I can install Qubes-OS without any problem”.
When I say “unavailable in Europe”, it means that if I want to find a computer of this kind, I’ll have to dig around, and maybe settle for a used one.
Understood. If you insist on buying a new one you will likely have to go with the Purism Librem 14 v1.
What do you think about it?
Since you are in Europe, I would strongly recommend the NitroPad T430.
If using Qubes OS is high on your list of priorities, you might need to let go of some of your other feature wishes. In general newer computers tend to be not supported well in Qubes OS, but do become well supported 2-3 years later. That’s unfortunate, but one has to pick ones battles and Qubes OS concentrates on security.