Currently, in the Zabbix git, there is the path

templates / app / proxmox

that only includes template for Proxmox Virtual Environment.

"Proxmox" is not the VE product but they (the company) also have other products (see https://proxmox.com/en/ ).

I suggest renaming the current proxmox directory in the templates to proxmox-ve, to further make it possible to distribute templates for the other Proxmox products as well.