It should work with tiled output, so long as a) it reports tiled geometry in DisplayID b) the driver handles it right.
Then it should show up as single display.
It's also how Apple XDR display presents itself to MacOS (two DisplayPort 1.4 tunnels over USB4, tiled layout in DisplayID).
I suspect it's possible that it doesn't have a valid tiled geometry block, but that's something that was already handled right when first 4k displays landed, so...
