Photoshop significantly decreasing RAW photo quality compared to other apps

Most other applications do not interpret the raw data - they display the camera-processed embedded jpeg.

The camera processed jpeg will usually have very aggressive noise reduction applied, as well as a high contrast curve that brings up brightness and saturation. Camera manufacturers have a very strong incentive to make the image as immediately appealing as possible. This is how they sell cameras!

In ACR you have to do all that yourself. You're not supposed to just accept the defaults, the sliders are there to be used.

A fact that most people miss when comparing raw processors - and the camera firmware is just another raw processor - is that the underlying sensor data are exactly the same.  The initial raw file is exactly the same. This is all about how that sensor data is interpreted. In ACR you control all the parameters in the conversion, but you have to use the sliders. In the camera, it's all done automatically without any user input.

There is no such thing as an "original" version of a raw file. It has to be processed to produce a recognizable image.

I’m not sure, but XnViewMP might be showing the preview embedded by the Canon camera, which would represent how the camera is set to process its own raw image data. If XnViewMP instead does actual rendering from raw, I don’t know which raw engine it’s using (maybe an open source one like libraw?). The way a raw image looks in Adobe Camera Raw is based on the Adobe raw processing engine and its current settings, which will usually render a different result than the camera or other raw processing engines.

I tried a couple of my own Canon raw images, and in Adobe Camera Raw I was able to get it to look more like the XnViewMP version by applying the raw profile Standard under Camera Matching. This makes sense because the Camera Matching profiles are designed by Adobe to better mimic the in-camera processing.

The difference in noise might be because of what your screen shot shows: No noise reduction is applied to the image in Adobe Camera Raw. But your image was clearly shot at ISO 3200, which usually requires noise reduction, so it really needs noise reduction set well above zero. (The in-camera settings might automatically apply more noise reduction to images shot at higher ISO settings.)

For many, the point of shooting raw is to use other software to make a better rendering than the camera defaults; in that case, the camera preview is disregarded as not a useful reference because it isn’t the intended final look. But, some people want the image to always start out looking like the camera rendition, so Adobe provides a way to do that: Setting your own raw defaults. By doing so, you can make the earlier suggestions happen by default. You can set up your raw defaults to apply the raw profile of your choice, or even your own profile; in this case, it sounds like you’d like the Camera Standard profile applied instead of Adobe Color.

You can also create camera-specific defaults (if you want to vary them by camera), and you can make the defaults ISO-dependent (so that you set how much noise reduction to apply by default for certain ISO settings).

You can add other settings that you want applied all the time by default, such a lens profile, tone curve, etc.

The steps are covered in these articles:

How to Create Custom Raw Defaults in Adobe Camera Raw (Julieanne Kost)

Set up default settings for raw images (Adobe Help)