Earlier quoted context omitted.
Gajim [1] implements a lot of modern XEPs (directly or through easy to install plugins), including OMEMO. I don't know how well it works on non Linux systems (they provide Windows binaries at least). [1] https://gajim.org/
it works. doesn't feel very native, but then neither do a lot of the big names in chat right now
Most of the "big names" who provide modern and contemporary desktop IM apps deliver on the 3 platforms (Linux, macOS, and Windows), and use mostly web "technologies" (sometimes "pure browser", and sometimes with electron-like desktop "packaging")... so as a consequence, it is very native, indeed, but it is a generally consistent and continuous UX (user experience) between mobile/tablet and desktop/laptop.