Even the current PSE 2022 could not support it natively. (edit: it has been updated automatically last June).
So, the 'normal' solution for you would be to download the free Adobe DNGconverter mentioned in that faq. That standalone application can batch convert a whole folder your R7 CR3 raw files to the universal DNG raw format that your current PSE version can read and edit with the same quality.
We have contacted Adobe and they say that Adobe 2018 (my question) Adobe Elements 2018 does not support the RAW files of the Canon R7. That's why we bought the Elements 2022 and they report that it does support the RAW files