>https://wiki.archlinux.org/title/XDG_Desktop_Portal
You are probably asked this question hundreds of times but are these the only WMs that let you override the gtk file picker used by firefox? The default file picker has no real thumbnails grid preview support but overriding it to portal fixes the issue. Problem is, not every WM supports this portal feature apparently? Or am I reading the wiki wrong?

File chooser portal / YES
>COSMIC
>Deepin
>GNOME
>generic
>KDE Plasma
>Liri
>LXQt
>theDesk

File chooser portal / NO
>Hyprland
>wlroots
>Cinnamon