Recommendations for (european) multi-language use

Hi! New to all of this, but I've been following the community for a while and wanted to finally get my hands on a board after having figured out what (I think) I like. Still have some questions concerning multiple-language use case. I read through some of the posts on here but couldn't find a lot so I thought I will just ask...

So far, following one comment, I guess it would be best to go with anANSI layout and learn how to use US International layout, since the (Keychron) Keyboard I currently eyeball is also difficult to get as ISO fully assembled in the color option I want, ordering from Europe. I need this to run on Linux and I guess there's no way around getting into key mapping.

1. I do work with several langues, so I would need at minimum Latin and Cyrillic alphabet, additionally some characters of Nordic, Slavic, Germanic and Romanic languages, so basically a lot of diacritics, but also a few extra characters such as ø, ß, ł. However, from what I read US International might not work with for instance Czech, which is a huge problem for me (š, č, ž, ů etc.). Anyone on here with experience and/or solutions regarding this?

2. For those of you owning and using a Keychron on Linux, is keymapping a no-brainer? (I hope my biggest issue with this will just be using a Chromium-based Browser xD) --> If Keychron isn't advised, any ideas on other Keyboards supporting key mapping, preferably manufactured in and shipped from Europe. (metal body, 80%, wired, media knob, possibly macros, price point less important)

3. Also looking for recommendations on where to buy aesthetically pleasing Latin/Cyrillic Keycaps! Preferably Europe-based Vendors and no sketchy and cheap (possibly toxic) chinese products.

Thanks a lot!