[CA] sick time for surgery recovery

hi, I am a california employee and couldn’t find any specifics about this online. I requested to use 1 week of sick time for a surgery in ~6 weeks (tonsillectomy) followed by one week of remote work. remote work was approved but my work said that I am not allowed to use my accumulated sick time for the first week because this (surgery recovery) isn’t an “illness” and that I would have to take time without pay or use vacation time.

I am specifically looking for legitimate resources that I can provide my work if the answer is in my favor. I did find resources saying this is federally legit as long as they provide unpaid time off, but just wanted to double check for california bc I know our labor laws are better in a lot of situations.