You can implement a microflow in which you ‘build’ your emailtemplate with the contents and needed tokens. This might seem a bit of a hassle upfront but in the end is always useful in resetting or starting a (new) environment.
You will also need to check/update the Modelreflection in the process so your flow would look something like this:
(right click > save for full image)
There are many ways to achieve this, but my preferred method is to export relevant entities into a .json format, then importing them in another environment. Using a microflow, you can retrieve the email templates from the database and export them into json format using an export mapping.
You can then create a page with an input field where you can paste the json, and import using an import mapping and committing the imported objects.
Thanks, I do now know how to approach this. There is no simple copy mechanism out-of-the-box available.