In case that helps someone, after I spent hours researching that, you can use Purevpn with LibreElec, but there are few manuals steps that I found on various threads (I am using a Raspberry3).
- Install VPN Manager for Open VPN (Releases · Zomboided/service.vpn.manager · GitHub)
- Download PureVPN Openvpn files from PureVPN website OpenVPN configuration file for Windows, iOS, Linux etc. (Recommended OpenVPN files Linux) using wget
- Unzip the archive downloaded
- Follow the steps explain in this wiki 09. User Defined VPNs · Zomboided/service.vpn.manager Wiki · GitHub to install PureVPN as User defined VPN as PureVPN is not supported anymore by this addon