I think it should be possible, since Webinoly supports PHP websites, and Nextcloud / Owncloud are written in PHP.
You can follow this tutorial for Owncloud and this tutorial for Nextcloud. Webinoly will already setup and configure the software you need, but you have to do all the correct configuration yourself.
Good luck, let us know if you succeeded. :)
I made no real progress in getting Webinoly to run Nextcloud so, for this project at least, I changed horses mid-stream and started running Docker containers for WordPress and Nextcloud.
This was far more successful and surprisingly easy to do with CapRover. In fact there's even a CapRover 1-click install at DigitalOcean.
Hmmm. I wonder if I can get Webinoly to run in a Docker container? :-)
Your regular donations is what keep this project moving forward. If you like Webinoly, buy me a coffee or a beer to show support.