How to avoid connecting multiple Word templates? The document is the same; only the signatures are different.

I have a screen-form that has the signatures of the users attached as an image file in PNG format, and depending on whom fills it out, the corresponding signature appears.

On the backside, I have attached Word templates for each unique signature. (Screenshots attached) It works, but this is not a long term solution as more users will join, thus more signatures.

Has anyone run into the same problem, or might have an idea on how I can minimize the number of templates to only one?

Thank you!