Proxmox VE

Hi All, I'm part of the association in my school, and we're looking to add new servers. I'm searching for a tool to manage the servers, create VMs, troubleshoot, and backup data. We currently use an old version of Proxmox VE, but nobody likes this solution, and we want a more recent and reliable solution.

I heard that Docker could be used for that but is it really reliable? Does anyone know a free tool (ideally open source) that will allow us to manage our servers efficiently?

Thanks.