> Best of all, it all works on whatever I can get on Media Markt, Saturn, FNAC, Cool Blue, Conrad, Publico, Dixons,...

You don't expect MacOS to work on an ACER laptop you buy at the nearest Mediamarkt right? Nor do you expect to be able to plug a windows installer memory stick and install it on an apple silicon macbook air right ?

With only a couple minutes of research it is fairly trivial to find laptops compatible with linux, especially if you stick to business line of laptops such as the thinkpads, dell latitude. I could install and use Fedora on the last 3 professional laptops I have been given by my employers, as in all personal computers I have bought.