I've personally found Genki's Covert Dock Mini to be wonderful - not only is it pretty inexpensive, it's also super-tiny. You'll need to charge any pro-style controllers separately though, as there's no port for it.

If a controller port is important to you, you can try the standard Covert Dock, which is a bit bigger and a bit pricier, but also works great.

I can personally whole heartily recommend the Genki Covert Dock. It's not 4k60 but it works perfectly for the Switch and my Odin. For 4k60 I've only ever used this Anker Cable but I can say that it definitely works great. Only issue with a cable like this is that you won't get charging.. I believe Anker actually makes some that has charging, but I can't confirm if they work as intended.

Also Genki is actually making a newer miniature version of their current dock for $20 less, but unfortunately it's only 4k30 and missing a USB port.. A bit of a missed opportunity in my opinion since I would have liked to see 4k60, but I'm happy enough with my regular Covert Dock that I could live without the 4k.

One other thing to mention, if you're trying to output in 4k make sure to check your TV. I tried one other cable before besides that Anker one I linked, and I thought it was either defective, or that it was my phone which is on an older version of Android. Turned out it was the HDMI ULTRA HD Deep Color setting on our LG screen locking it to 4k30.