[OnePlus Nord Themes, Apps, and Mods] S4turno:
@mythos_

Regarding the size:

The size difference can be related to the inclusion of custom libs on greatness' version. More libs = larger file size. Some people like using them over the stock "google" one to avoid crushed blacks and more detail by default (without the need to use lib patcher), but from experience, those often work well in certain conditions but result in weird colours under other conditions (haven't tested the ones included, might be different).

I don't know if any of the apps use compression, but it can also reduce the app size, with a small performance hit when opening the app.

"Nord front wide fix":

Without it, HDR+ Enhanced doesn't work on the front wide camera (photo not saved). Greatness calls it "nord front wide fix", Wichaya calls it "Override base frame index", but it's the same thing.

Urnyx05 never included it on his version, that's why I suggested using Wichaya or Greatness as they are based on Urnyx and include this fix.

Contrast, saturation, night vs day:

Back in 2017, when people started modding GCam, it was way easier to compare GCams because we couldn't change much. Since config files were introduced and now with Lib Patcher, you can tweak so many values that the same GCam apk can create both files you like and files that you dislike.

For example, the type of AWB used will affect photos. There are different ones because while the sensor is the same, things like the lens/"glass" used affects the output. And then you have custom libs, levels of saturation, contrast, lib patcher values focused on detail or smoothness, etc.

I think it's fair to say that apps that share the same base should create similar files if properly tweaked (time consuming/hard to do). The only exception that comes to mind is UltraM8's version. It's based on Arnova8G2's version, but the default lib was modified to do one thing only: take detailed photos with the rear main camera.

Can we create one good config that pleases everyone? Nope. People like different things and use their camera in different ways.

For example, I like detailed images and flat colours (even my display is only RGB), but some people prefer more vivid colours or less details because they take selfies and don't want to look "old". I don't mind HDR enhanced taking a bit longer to capture a picture, but too many frames is bad for someone wanting to take pictures of their kids or moving stuff. Good values for outdoors pictures might not be the best ones for selfies or low light photography.

To be safe, configs for new users (or users that don't want to test) should try to find a middle ground between the extremes. Maybe 9 or 12 frames instead of 20, details, but not too much, and so on. It won't be the best possible config, but the only alternative I can think of is to have multiple configs (someone needs to create them) and have users pick the best one for them/for they want to do in the moment.

Differences between versions:

I guess one could check the changelogs, but it's not easy.

There are visual differences (Wichaya re-organised the settings menu), some small features are available on Greatness and not on Wichaya (and vice-versa; eg: default JPG quality), greatness comes with custom libs and worked with "Timo" to create detail-focused configs for the OP7, Wichaya handles extra cameras better on some phones, supports more devices, and is more popular.

Which one is better? No idea, but both are good.

I usually keep more than one version installed on my phone and have at least two configs: main and low light (with more aggressive, detailed-focused lib patcher values and enabled AWB).

This wasn't as important on my previous phone (OnePlus 3). I could use the same settings for most stuff and it would be ok. To give you an idea, I took this on the 2018-19 new year's eve with the OnePlus 3 and this a year later with a Zenfone 6 (same sensor as the Nord). Both produced similar pictures during the day, but in low light... it's a big difference. Neither pictures are particularly good, the one from the OP3 is noisy and has a pink tint, but at least isn't a blurry mess.