Ah, that. Wayland by itself doesn't prevent nothing from keylogging, you can only be sure that (in GNOME or KDE cinematic universe) keylogging by listening on X-things or the socket can be achieved only tampering with LD_PRELOAD or the kernel and not by design (unless one or some apps would redo that Xorg POF).
When Wayland was born you couldn't do anything to prevent that, now we have like 6 sandboxing/light-virtualization options for Linux, so I suspect that by containerizing applications in Xorg you could prevent them from keylogging easily. That too right now is mostly crappy and fragmented in Linux with the AppImage Snap and flatpak circus.
Of course Wayland can’t secure your kernel or rtld, but I’m pretty sure that one of its advantages is that it can at least not send a random app the password you’re typing in.
And no, I don’t think you can really do that with x11. There was Trusted X11 long time ago, but I don’t think it was practically useful - as in, maintainable and sustainable.
As far as I understand sandboxing in Linux is “70% there” - it will get there eventually, but for now the 30% hole makes it not practically useful. It’s not bad at pretending it’s doing something though, and for (many? most?) paying customers that’s enough.
When Wayland was born you couldn't do anything to prevent that, now we have like 6 sandboxing/light-virtualization options for Linux, so I suspect that by containerizing applications in Xorg you could prevent them from keylogging easily. That too right now is mostly crappy and fragmented in Linux with the AppImage Snap and flatpak circus.