F11 toggles the Styles sidebar (in non-full-screen view..).
Try Shift+Ctrl+J to toggle Full Screen. If that doesn't work (non-English UI, other key bindings, ...) try Shift+Esc that presents a search command input field, enter full and it should list "View -> Full Screen" (in English UI); hit that.
Gitea has tea and Forgejo/Codeberg has berg, see also https://docs.codeberg.org/git/clone-commit-via-cli/#gitea-%2F-forgejo-cli-tea
Bad clickbait headline.
Depends on what your language's script is then with assigned Unicode characters, how wide-spread it is, when fonts will support the glyphs, and what you mean by "changes to be available on my local OS". What OS? What does available mean here? Do you expect the OS UI to be in your language? Doubtful. Some desktop environment maybe somewhen. Programs using ICU are more likely to support specific script related features (e.g. word/line breaking, transliteration) when ICU will support Unicode 16 in its next version. Locale specifics may have to wait for or could be contributed to CLDR that is also used by ICU. Availability of any UI in the language mostly depends on whether translators contribute to the relevant projects.
They are "looking for a more private" client. With the centralized Discord service that does anything it wants with any message there is no such thing.
Whatever client you use, there is no privacy with Discord. Period. Full stop.
There was the particular LiMux one in Munich that was "solved" by Microsoft moving their head quarter to a district of Munich and the then new conservative coalition in town government thanked them by rolling all back and buying MS products instead.
Someone gave a little overview in that Hacker News topic mentioned.
In F-Droid https://f-droid.org/en/packages/com.google.android.stardroid/