Get current user email and add to collection

Don’t use the old and depricated Wix-Users-API !
Instead use the new MEMBER-API…

https://www.wix.com/velo/reference/wix-members

Also do not bump-up old posts, instead open your own new one and describe your own issue. You can link other related possts to your own.
This is an example why you shouldn’t do that.