Can I edit my Canon 90D CR3 files in Camera Raw using Photoshop Elements 2021?

Not having camera matching profiles simply means Adobe hasn't provided "camera faithful" profiles. However, there will be profiles such as Adobe color, Adobe landscape, Adobe vivid, etc. Profiles are only starting points anyway. There is an arsenal of excellent controls to enable you to modify the settings to achieve the optimum results that you desire.

” Support for a particular flavor of a camera’s raw file does not necessarily mean that there will be Camera Matching profiles for that camera at the time of raw file support. It is normal for Camera Matching profiles to follow raw support by one or two releases. In the case of some camera manufacturers or the event of major changes by a particular manufacturer, that time may be greatly increased.

Note: Not all cameras will ever receive a set of Camera Matching profiles. ”

https://feedback.photoshop.com/conversations/camera-raw-and-dng/what-does-camera-support-mean/5f5f46244b561a3d4275ca34

Moved to the Camera Raw forum, from the Photoshop forum.

You are wrong 🙂

When you adjust a raw image in camera raw there is no right or wrong way to adjust it. However, for some cameras, a profile can be used that makes initial adjustments that are close to the jpeg presets in your camera, hence camera matching profile. That gives you a starting point but, personally, I've never let those bother me and I just adjust each image to taste and to suit the image itself.

Dave