Not at all in my plans. The plugin structure is very different, and much more limited--for example, AFAIK, you can't feed a FQDN to a plugin installation, so that it will configure the instance you're installing to use that FQDN. There's already a Nextcloud plugin, so if you want a plugin, use that.
- I use Caddy as the webserver; the plugin (IIRC) uses nginx
- Partially as a result of the above, the installation created by my script will automatically obtain and renew TLS certificates from Let's Encrypt and/or ZeroSSL. Last I checked, the plugin doesn't support TLS at all.
- My script completely installs Nextcloud--once the script finishes, it's ready for you to log in. Last I checked, the plugin gives you a half-assed installation where you still need to enter database credentials, create an admin user, point Nextcloud to where its data is stored.
- My script stores all the data--the database, the uploaded files, any themes, even the Nextcloud config file--outside of the jail. That means that you can destroy the jail without losing your data, and reinstall in a new jail and have it pick up your existing data. Last I checked, the plugin doesn't do any of this.
Doubtless there are others, but that's what comes to mind. You'll notice a lot of "last I checked"--I'm not too interested in the Nextcloud plugin, so I don't pay a lot of attention to it other than what I see reported in various threads here. Maybe some of this has changed.
Probably. Stop the existing jail, turn off "start on boot" for that jail in the GUI, change JAIL_NAME in the config file, and then run the new installation. If it doesn't work, you can revert to the old jail.