Proton emails are stored in an encrypted form that goes beyond the simple authentication that is part of the POP/IMAP specifications
Proton does have open-source bridges/proxies, so they aren't hiding these details from us
Perhaps Thunderbird could be enhanced to support the Proton features directly?
Not disagreeing at all, but I'd like to add some information here to support your correction
There's a GlobalShortcuts portal ( https://flatpak.github.io/xdg-desktop-portal/docs/#gdbus-org.freedesktop.impl.portal.GlobalShortcuts ), and this is implemented for hyprland in xdg-desktop-portal-hyprland ( https://github.com/hyprwm/xdg-desktop-portal-hyprland/blob/b2fc1110963fa583ad5348a9dc0101bd58ceac7a/hyprland.portal#L3 )
So, technically, there is nothing in the wayland collection of protocols that supports global keyboard shortcuts, but (along with lots of other supporting functionality), this is addressed via the collection of portal APIs
As it happens, KDE already supports the GlobalShortcuts portal: https://invent.kde.org/plasma/xdg-desktop-portal-kde/-/blob/master/data/kde.portal#L3
Any desktop can provide an implementation of the GlobalShortcuts portal, and any app can adopt it as required (although if it's implemented within popular toolkits/frameworks, then app developers won't have to even think about it)
Here are related tracking issues: