Nadiyar V2.7 on Nostr: Yeah... Java libraries for creating GUIs haven't got much love in the last couple of ...

Yeah... Java libraries for creating GUIs haven't got much love in the last couple of years so they look (are) outdated also since there's no implementation or reliable wrapper of GTK or QT they always look alien

Though for your second difficulty I don't understand how this is an issue for users. Installing Flatpaks or just using distro's package manager should resolve your problems.
Also good to remember building programs from source is ALWAYS a bad idea.