The fact you're griping about implementation details like pipewire makes me think you also tried micromanaging your env and broke something. If you use a fresh install and leave everything default, I'm sure it would work for you like it does for everyone else. I use KDE too btw.
All the "micromanaging" you need to do to not have screensharing is one of the following;
1. Don't have a started dbus session
2. Don't have portals installed and setup
3. Don't have pipewire installed and setup
Meanwhile on X what you need is:
1. Have X
So no, it wouldn't work, the reason why it works for those people in the Reddit post is because they use distros and sessions that do all the things I listed that make screensharing not work if any one is not done.
PS: Wayland does have testing protocols for screenshots and screenrecording like 'wlr-screencopy' and some DMA buff one I forgot the name of. But for screen sharing there's nothing that Wayland implements itself afaik.
Without dbus, X would also have plenty of its features fall flat, it's the de facto IPC mechanism of Linux desktop for better or worse, so it's like "my car won't start if I don't have any fuel" complaint.
The fact you're griping about implementation details like pipewire makes me think you also tried micromanaging your env and broke something. If you use a fresh install and leave everything default, I'm sure it would work for you like it does for everyone else. I use KDE too btw.