It's a little bit amusing to me that that FastSnail adapter says:
DISSIPATE HEAT - The heat dissipation of Nintendo Switch Dock is not so good and it makes the console hot. But use our HDMI adapter, you will never worry about this problem.
...when in order to use it, you place the Switch on its back which then blocks intake vents. Whereas if you use the official dock there's a small gap between the Switch and the dock so it can still pull air in.