Zip and unzip don't support SOURCE_DATE_EPOCH at present. Specifying the --no-extra / -X option will remove most of the timestamp fields, but not all of them.
Every zip file includes a mandatory DOS last modified date/time field. See section 4.3.7 and 4.3.11 where it mentions the "last mod file time" and "last mod file date" in https://pkwaredownloads.blob.core.windows.net/pem/APPNOTE.txt To get SOURCE_DATE_EPOCH support the "last mod file time" and "last mod file date" fields would need to be changed to use the SOURCE_DATE_EPOCH. If that was done, it would be worth adding similar support to the other extra fields that store file creation/modification/access date/times. Then the reproducible build would no need to specify -no-extra.
