Lightroom 6.14 doesn't support the Canon EOS R6 Mk2. Support requires version Lightroom Classic 12.0, which is subscription only. The alternative, if you want to stay in the Adobe ecosystem, is to convert your Canon CR3 files to the Adobe DNG format using the free Adobe DNG Converter.
Note that the DNG Converter requires macOS 13 (Ventura). Therefore, you will also need to upgrade your OS
I've provided a link to the DNG Converter below.
https://helpx.adobe.com/uk/camera-raw/using/adobe-dng-converter.html
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