Open URL button w/URL parameters (ninox replacing characters)

Hello, Ninoxians! I am trying to create a button that will open a URL and pass parameters into that URL from my record; however, Ninox is replacing parts of the URL with different characters. Ninox is replacing

{ with %7B

% with %25

} with %7D

Note: I've added a space to URLs so that they do not get flagged for review.

My code:
let URLFirstName := replace('First Name'," ", "%20");

let PhoneNoLParenth := replace(Phone, "(", null);
let PhoneNoLRParenth := replace(PhoneNoLParenth, ")", null);
let PhoneNoSpace := replace(PhoneNoLRParenth, " ", null);
let UnformattedPhone := replace(PhoneNoSpace, "-", null);
let TextURL := "https:// www.example .com/Doorstep1/TextMessageSender?entry={%22CustomerPhone%22:%22" +
    UnformattedPhone +
    "%22&{%22CustomerFirstName%22:%22" +
    'URLFirstName' +
    "%22}";
openURL(TextURL)

Input:

Phone: (123) 456-7890

First Name: John

Expected result: 

https:// www.example. com/Doorstep1/TextMessageSender?entry={%22CustomerPhone%22:%22 1234567890%22&{%22CustomerFirstName%22:%22John%22}

Returned Result:

https:// www.example .com/Doorstep1/TextMessageSender?entry=%7B%2522CustomerPhone%2522:%2522 1234567890%2522&%7B%2522CustomerFirstName%2522:%2522John%2522%7D

Does anyone know how to get around this?

^I added a space above to each URL so that the post didn't need to wait for approval.