Docker has been a fundamental part of my setup for more than three years now. Day after day I tried to move as many services as possible to Docker and this was a very good move.
Proxmox Backup Server (PBS) has been released. It's still in beta but is already perfectly usable. After many years, it's now possible to perform incremental backups of the VMs and thanks to the qemu dirty bitmaps, backups are also fast.