Wall of code for form and $_POST

Hi team, its been a long two days in an attempt program a plugin from scratch to provide a front end landing page with 2 forms.

Depending on which form the user wants to use, the form shall change a value in the database (add or create if nonexistent custom field “key”=>”value”).

Without luck, many several changes were made to the forms and the functions associated to manipulate $_POST and getting its value etc and without success!

Is someone willing to take a look at my code below? The goal is to differentiate between two forms at the time of submission. After which, if the second submit button is pressed, a custom field value is updated in the wp_postmeta table.

I tried pasting the code here, but its not going through.
Please see
https://pastebin.com/6jZBzmXW