You need password, salt and IV. So it cannot work yet.
Create these three things in Setup, Key Management, in the BU where you want to encrypt.
And, if separate, create the exact same three things also in the BU where you want to decrypt.
Password: Key Type = Symmetric, it is not specified how this should look, so use something with around 25 characters and ...
Your AMPscript variables @EMAIL, @NAME, and @MOBILE are empty. That is why you end up with only parameter names but no values in the submission link. Unfortunately, you cannot capture input values with AMPscript since it is a server-side language that is executed once per page load.
To achieve what you want you need either to configure a form handler or pick ...
you are inside an AMPScript definition block (opened by %%[ and closed by ]%%) so you do not need to (in fact, shouldn't) add the inline ampscript markings (%%= and =%%) for functions inside it.
This should be more like it (when used on a cloudpage):
IF @Status == "Yes" THEN
CloudpagesURL() is a ...
Since you are specifically asking for a workaround - use inline AMPscript in the preheader. If that gets messy, you can also use %%=ContentBlockByKey('SomeContentBlockCustomerKey')=%% in the preheader, put all your logic into that content block and the contained AMPScript should render at the right time.