This has been talked about quite a bit over on the Unravel Speedrunning Discord but it should be posted here as well
There is a technique some of us PC runners use we've called "Uprunning"
On a keyboard (as seen is DonDoli's WR Run) Yarny will gain extra speed by holding the Up Arrow Key in addition to the Right or Left Arrow Keys
This makes a lot of more difficult jumps easier, as well as other jumps and various things possible that aren't possible otherwise
I also run on PC using a PS5 controller, this is also possible by mapping the Up Arrow Key of the Keyboard to the R1 Button (any button you choose will work, I just chose R1)
Here is how to set this up for a controller on PC
Open Controller Layout
Click Edit Layout
Click whatever button you wish to use as the Up Arrow of a keyboard, in my Case R1 (or RB for Xbox)
Lastly Click Keyboard and Select the Up Arrow Key
The R1/RB button is now mapped to the Up Arrow key of the Keyboard
This will allow you to use the analog stick for normal movement and use the R1/RB (Up Arrow) as a type of speed boost
As for Console Runners
I'm not sure if there is a way to remap buttons on an Xbox but I did some testing of my own on my PS4 and while there is button remapping options, there isn't a way to map the up movement like this.
It seems holding the analog stick at an upward angle may give Yarny a speed boost sometimes but it's a very precise angle, I could not get it consistent, and I personally wouldn't depend on it
This does give PC runners a very distinct and large advantage imo
So as a result of doing this the playing field is fairly lopsided
I am still looking for ways to do this or something similar on Console but haven't found a way to do it yet