It turns out that the Nintendo Switch OLED Model comes with a 4K and 60 Hz-capable dock. Available to purchase separately, the new Switch Dock also has an integrated LAN port.
https://www.notebookcheck.net/Nintendo-Switch-4K-and-60-Hz-support-may-come-to-the-OLED-Model-via-a-dock-firmware-update.571763.0.html
The original switch came already with a hdmi 2.0 cable and a pretty good at that.
As said by MVG: they probably have the 4k chip due to price as the 4k chip is widely used and therefore cheaper than the old chip
Every desperate tech website: Nintendo is releasing a 4k Switch!
Nintendo: For the last time, we have no plans for a 4k Switch.
Every desperate tech website: Did ya hear that, folks! Nintendo IS releasing a 4k Switch!!
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C'mon guys, just enjoy the Switch for what it is. Obsessing over 4k gives the impression that you think great graphics = great games. That's far from reality.
Every desperate tech website: Nintendo is releasing a 4k Switch!
Nintendo: For the last time, we have no plans for a 4k Switch.
Every desperate tech website: Did ya hear that, folks! Nintendo IS releasing a 4k Switch!!
-----------
C'mon guys, just enjoy the Switch for what it is. Obsessing over 4k gives the impression that you think great graphics = great games. That's far from reality.