Assuming when you say “templates” you are refering to the various “template databases” ....
Sort-of-kind-of-Yes.. Using the Mac app, you can download the database templates to your local machine.. Then, either from one template.. or a brand new database you can “import” from another Ninox database. When importing, it will ask you if you want to import the data model, data, and files. So that is the “yes” part..
The “Sort-of-kind-of” .. part is, if the source from which you are importing uses “global script definitions”, those are NOT imported automatically (or at least the last time I imported they were not).