In Digital Foundry's latest piece, they experiment with pushing the Switch's CPU and GPU clocks to the maximum that the Tegra X1 supports, so see what effect it has on games. 

For the GPU, it's pushed from its normal docked clock of 768MHz to a max of 921MHz, roughly a 20% increase.

For the CPU, it's pushed from it's usual 1020MHz to 1785Mhz, about a 75% boost.

https://www.eurogamer.net/articles/digitalfoundry-2019-switch-overclocking-analysis

The gains vary greatly on a game by game basis, depending on whether a title is limited by CPU, GPU, or memory bandwidth.

Here's the interesting part though; even when fully overclocked, the Switch, in docked mode anyway, only increases in heat from 60 degrees to 68 degrees; well below the system's throttle limit of 83 degrees.

Therefore, in theory, there is room for Nintendo to continue to unlock more of the Tegra X1's power over time, as they have already done by offering a 460MHz overclock in portable mode and more recently the full-speed CPU "boost mode".

Now, the CPU was most likely kept low to ensure parity of gameplay between docked and portable play, but graphics scale more readily, especially in this era of dynamic resolution, so opening up the option for devs to run at 921MHz in docked mode could make for a better TV experience. Again, they've already allowed for an increase in portable GPU clocks, so why not also docked clocks, where battery life is not an issue?

Instead of making a "Switch Pro" with better specs that leaves existing users shortchanged, Nintendo could simply allow developers to use higher clockspeeds on the existing Switch; it will run a bit hotter and make more fan noise, but owners of a base Switch won't have to deal with subpar performance.

from the few titles tested there seems to be little gain from only overclocking the GPU, as the CPU seems to be the limiting factor much more frequently

that said almost all the games they tested were developed for a different main platform and ported over

A) Nintendo wanted to keep parity.
B) Most importantly, it was for battery purposes.

Key takeaway, handheld mode is the most important element for Nintendo. Docked mode is held back, rather pointless endeavour in my opinion.

It's mostly CPU and memory bottlenecks.
Given that they've already broke "switch" part of Switch with Switch Lite, there's no reason not to make Switch "docked" only with higher specs.

This might be a good way to go for extra docked performance.

Like I know power consumption would probably double or more, if you ran ~1800mhz on cpu + ~920mhz on gpu.
But honest who cares? The Switch is only useing like 20watts or so, docked... it going over 40watts wouldnt be a huge issue (as long as cooling allows for it).

Maybe make a docked only switch version?
With how little cooling is needed, you could easily make a switch with the same chip, that had those speeds.
(allowing for better docked performance/graphics)

I dunno, my switch already feels hot enough to cook an egg on while docked without boost, I dunno if I'd risk it. Although I have a hacked switch, so maybe mine runs hotter.

I'd be tempted to overclock just for Xenoblade chronicles 2 alone. That game runs terrible, I was hoping they would show a comparison of it in the video. 

On dock mode it runs decently. On portable mode on the other hand... it runs like shit

I'm fine with the Switch and the graphics it can produce. It probably helps I grew up playing NES games. Either way, Nintendo wanted seamless transition between portable and docked; for the most part the Switch delivers.

I mostly play it portable in bed, should probably remedy that.