You can apply settings in any Revit project that make it be exactly like done with your template, even if a different template was used. A template does nothing that can't be done afterwards to any project. It is just a time saving feature to pre-set things once instead of doing it over and over for each project. and there is no digital signature or similar feature "proofing" what template was used.
A while ago there was a thread about this and there IIRC the OP wanted to enforce that employees use the approved template and proof if they didn't.
I personally don't even use templates, I use a default starter project. it does the exact same thing as a template fire minus some limitations templates have. If I wanted, I could turn it into a template file or vice versa.
Maybe explain our actual objective.
Revit Version: R2026.2
Hardware: i9 14900K, 64GB, Nvidia RTX 2000 Ada 16GB
Add-ins: ElumTools; Ripple-HVAC; ElectroBIM; Qbitec