I tried to install in a normal debian 10 LXC using the curl script. However, I never got it working and got errors.
After quite some research and asking for help I finally gave up as I could not find out how to solve the errors that came up.
Even though there where people who seem to have succeeded. LXC 路 Issue #1058 路 nextcloud/nextcloudpi 路 GitHub
It would be amazing if you @Kerasit could share how you got around the issues.
I think there are a number of people who are looking to have a NCP LXC up and running on Proxmox.