How to map an object to arrays so it can be converted to csv?

Question

Try this filter:

to_entries[] | [.key, .value]

to_entries converts an object to an array of key/value objects. [] breaks up the array to each of the items in the array
then for each of the items, covert to an array containing the key and value.

This produces the following output:

[
  "123",
  "abc"
],
[
  "231",
  "dbh"
],
[
  "452",
  "xyz"
]

Then you can use the @csv filter to convert the rows to CSV rows.

$ echo '{"123":"abc","231":"dbh","452":"xyz"}' | jq -r 'to_entries[] | [.key, .value] | @csv'
"123","abc"
"231","dbh"
"452","xyz"