There are numerous working ways to handle this. But nothing as simple as you may preffer.
Since you are working with ezviz and not Hikvision, there are some limitations to it. Ezviz is more prone to being locked with such options as a default.
I have working script for Hikvision and ezviz to save images every X min/sec/hours. But it require API keys for integration.
It may work as a local service, or a cloud service.
I mean, idk how to even explain so it doesn't sounds too complicated for you.
Lets put it this way. If your APP/Camera does not offer this as a default option. It most likely does not support it, and in order to do something like this you need custom made solution. And custom made solutions are rarely a double click script done. Specially for this scenario. You would need a machine where script will be ran on as a server, OR you will pay cloudbased application that will work instead of your physical machine. Either way it has costs.