Customizing template files

We have a client who has custom post blocks on their home page with a very specific layout. We use Flexible Posts Widget to do that, but the plugin appears to be abandoned which is why we’re looking at Flex Posts now.

Because Flex Posts has a template files, I was able to modify one of them to give our client the layout they want. However, as soon as we do a plugin update for Flex Posts, those changes will be overwritten, and we’d like to avoid that.

Is it possible to create a copy of your template file(s) and store them in the theme folder so we can make layout modifications?

thanks!