The English translation for this just seems really clumsy unnatural to me. In conversation, I would personally word it as "I work every day but Sunday".
'I work daily except Sunday' would be another option.
"I work other than on Sundays" I feel should have been accepted.
Agree, just seems like extra assumed words added in the answer.
"on" is optional
Could be a good title for a priest's memoirs, depending on the meaning of the sentence. To me it meant "I don't just work on Sundays."
I work apart from on Sundays was my answer.
Not a natural sentence!