you probably cant do the_field inside a plugin unless you’re absolutely sure it loads after ACF.. I’m not too sure about it..
Perhaps you should look at some existing plugins to help you out instead 🙂
Seriously powerful which I use on most networks which have multiple sites with the same basic setup
https://premium.wpmudev.org/project/new-blog-template/
Let users switch theme after registration
https://premium.wpmudev.org/project/advanced-theme-switcher/
