If your zip file is corrupt then no wiping will change anything.
You'll need to redownload the file, and check the checksum to see if it's been corrupted during transfer. If yes, you may want to redownload it again, using a different mirror.
Alose, be sure to get the right OpenGApps package for your Android version and device CPU architecture.
My bad, I didn't read your whole comment. Have you tried reinstalling TWRP (again, checking the checksum) ? If EVERY zip file is seen as corrputed by TWRP, it might be your storage that's damaged. Using the "Repair" function may help.