connect the custom signup form to both CRM and a data collection

i have created a custom sign up and it is working fine, here is the link for the thread.
https://www.wix.com/code/home/forum/community-discussion/how-do-i-show-message-after-user-registration ,however since i have read that i won’t be able to do duplicate check for the ( username, email, phone number) at wix crm then i have to also insert the data in a data collection and apply the search for entries to make sure there is no duplicates.
i have came across the following thread https://www.wix.com/code/home/forum/wix-tips-and-updates/example-no-database-duplicates i tried to apply it but it is not working.

i have two main questions:
1- how to check for duplicates for three entries in my form.
2- how to put the code in a way that will check these entries in the datacollection before sending them to wix crm.

i would appreciate if that someone can help with the code, not referring to some links as i have seen all the links and filtered all youtube and i didnt find the solution for it.

this was covered about a day ago in a previous post