I can’t stand how my switch has such washed out colors on my TV in docked mode. HDR 10 is a must.
You should ensure that both your Switch and TV have the same range configured-- for various reasons, many legacy signals have 16-235 as the black to white range instead of 0-255. If your Switch sends 16-235 and your TV wants 0-255, you'll see a washed out image that doesn't have pure blacks or whites.
After that, you can tweak HDR emulation to get a tolerable image. Not true HDR, but it should look good. "works on my machine" (LG OLED B7).