This is not possible yet but it is a suggested enhancement - vote / follow it at JSWCLOUD-17277
You can also see what is coming soon on the Public Roadmap - for example there are new board settings coming soon that'll let you customise your view of the board, albeit it doesn't specifically mention card colours here.
...ollected feedback from users around the lack of shortcuts, and we’re here to address that: In next-gen projects, I miss the keyboard shortcuts badly. This is particularly true on the Board, but also i...
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