We have a requirement in which a custom date field is displayed in the format:
How can I achieve this at the Site Column level? Does it require JSON Column formatting? I do NOT want to use a Calculated field.
It's impossible to apply custom string formats using column formatting currently. Please see custom formatter reference https://docs.microsoft.com/en-us/sharepoint/dev/declarative-customization/column-formatting
Operator supported for date fields are:
toLocaleString() toLocaleDateString() toLocaleTimeString()
So I think calculated column is your best option.