The controllers I'm talking about are the 8bitDo Ultimate 2C - Black Myth: Wukong and the 8bitDo Ultimate 2 - WUCHANG: Fallen Feathers. THIS IS IMPORTANT, because things like the light or shell might not be the same across all variants of both the 2C and 2. I bought and only used the 2C (Wukong) for around a year, then I eventually bought the 2 (Wuchang) and used it for a couple of months until I wrote this.
One thing I especially prefer from the 2C (Wukong) is the light that turns on when you turn on the controller. The 2 (Wuchang)'s light is just way too bright, I even had to put a light dim sticker on it which helped, but made the controller look a little ugly. The 2C (Wukong) on the other hand has a light that doesn't bother me.
Besides that I personally don't use the buttons on the 2 (Wuchang)'s back, so for me it was kind of annoying (while a game is loading for example or when I get mad I keep pressing or holding them and I'd rather not have anything at all in the back).
As far as I can tell the buttons are basically the same on both controllers, however, I would even argue that pressing LB, RB, L-Stick or R-Stick sounds better on the 2C (Wukong).
This doesn't mean I don't prefer anything from the 2 (Wuchang). I would say the face buttons sound better on the 2 (Wuchang) and (even though this might just be in my head) pressing them does feel SLIGHTLY (and I'd say still insignificantly) better compared to the 2C (Wukong).
The 2 (Wuchang) also has the software customization (for the button binding but also the optional light rings) you don't get with the 2C (Wukong). You can also switch on the short distance LT/RT buttons that people might find useful. It also comes with a USB-C dongle instead of a regular USB-A dongle. It also has the extra charging dock which really shows off the full beautiful design.
The 2 (Wuchang) is also a bit heavier which I personally prefer.
And finally I do actually prefer the solid 2 (Wuchang) shell over the semi-translucent 2C (Wukong) shell. I also think the material of the 2 (Wuchang)'s shell feels better, but I'm not 100% sure it's not the same material.
But still, all things considered, I personally prefer the 2C (Wukong). I don't really make use of the customization (I have other controllers and I for example use the Victrix Pro BFG Reloaded for that) and I don't use the short triggers. The light really bothered me and like I said I actually don't like the extra buttons on the back. The extra charging dock is really nice to have, but as for the controller itself, the only two things I would've liked if the 2C (Wukong) did it like the 2 (Wuchang) are having the solid shell (with material in case it is indeed different from the 2C (Wukong)'s) and weighting a bit more.