RAW files from 1DX MK111 CR3

Your files are supported in Lightroom. Either Lightroom 3.2.1 (cloud version) or Lightroom Classic 9.2.1 (desktop version)

No, it's not yet supported as was to be expected. It always takes some time after the release of a new camera for Adobe to provide a converter. And it's even slower for the Elements Camera Raw module.

Your camera has just been supported in the beginning of this month for the full Photoshop (ACR version 12.2).

PSE 2020 only offers ACR version 12.0, and nobody can tell when it will be updated to 12.2.

So your choice is:

- to use the conversion software provided by Canon for your camera and to convert to tiff format.

- to download the free Adobe DNGconverter (12.2) which can batch convert a whole folder of your raw files to the DNG raw format that PSE2020 can read and edit. An additional batch step, but free and with the same quality.

https://community.adobe.com/t5/photoshop-elements/faq-will-photoshop-elements-work-with-my-camera-or-why-won-t-my-raw-files-open/td-p/4303022?page=1

Your raw files require camera raw 12.2 but PSE has only been updated to ACR 12.0

You could download the free DNG converter and batch convert a folder of CR3 files to use in Photoshop Elements.

Get the latest DNG Converter Mac OS | Windows