Ability to make Template mandatory & default an existing value in Create Negotiation popup UI?

Summary:

Is it possible to make the "Template" field mandatory & default an existing "Template" value in Create Negotiation popup UI using Page Composer?

Content (required):

We have a large number of templates defined but often user skip the "Template" field in the Create Negotiation popup UI as the field is not mandatory. This requires significant rework. We would like to:

1. Make the "Template" field mandatory
2. Default to a specific value for certain users

Any guidance about how page composer can be leveraged to make these changes will be very helpful.

Version (include the version you are using, if applicable):

22B