Proxmox wont make backups to B2 easier, but since it is basically a web interface and API for Debian and KVM/QEMU you might be able to use your current backup strategy with very little modification.
As for ZFS, you can expect to use about a GB of RAM for each TB in a ZFS pool. I (only) run 2x 4TB drives in ZFS mirror and it results in about 4-5 GB of RAM overhead.
Another point you might want to consider is automation and the ability to use infrastructure as code.
You can use the Proxmox Packer builder and Terraform provider to automate building machine images and cloning virtual machines.
If you're into the learning experience it's definitely a consideration.
I went from backing up entire VM disks to backing up only application data, making it faster and cheaper. It also enabled a lot of automated testing. For a homelab it's a bit much, the learning experience is the biggest part. It's an entire rabbit hole.
Proxmox wont make backups to B2 easier, but since it is basically a web interface and API for Debian and KVM/QEMU you might be able to use your current backup strategy with very little modification.
As for ZFS, you can expect to use about a GB of RAM for each TB in a ZFS pool. I (only) run 2x 4TB drives in ZFS mirror and it results in about 4-5 GB of RAM overhead.
Another point you might want to consider is automation and the ability to use infrastructure as code. You can use the Proxmox Packer builder and Terraform provider to automate building machine images and cloning virtual machines. If you're into the learning experience it's definitely a consideration. I went from backing up entire VM disks to backing up only application data, making it faster and cheaper. It also enabled a lot of automated testing. For a homelab it's a bit much, the learning experience is the biggest part. It's an entire rabbit hole.
If you want to see how the automation looks like, check out my example infrastructure repo and the matching tutorial. Also check out my Alpine machine image repo which includes automated tests for image cloning, disk resizing and a CI pipeline.