Note by @franticbiscuit

@slembcke @dotstdy I'm not really following the rest of the thread, but did want to reply to this specifically.

They have portable 4k monitors in the 15.6 inch -> 18 inch range on amazon. So 2x scaling on those monitors looks more or less identical to what you would be seeing on a mac. Source: Own one of them.

Anyway, I've learned that regular USB-C cables (non-thunderbolt) work on the 5k LG displays. It displays at 4k resolution, but with the PPI of the monitor you can't -really- tell that much. So I've settled on that with 125% scaling.

Also gnome -does- display @ 5k resolution over thunderbolt. X11 works as does wayland. X11 is better, as it has no tearing. Wayland has tearing in the center of the screen. At least, on the LG 5k monitor. You can find desktop computers that have working thunderbolt ports (both AMD and Intel). Some of the AMD x670 motherboards have thunderbolt ports, they just don't advertise them as thunderbolt.

Good luck!