I know I might be a little late here. But I highly recommend setting up proxmox as your base system and then use VMs (Virtual Machines) for your different systems (Hassio, Plex,…).
I have that setup running for about 1-2 years now and I don’t wanne miss it.
Not only the ability to take a snapshot of the whole hassio machine before doing a HA update (so good if something goes wrong with the update or some crucial part of your system doesn’t work anymore after the update), but also regular config backup of HA and complete backups of the VMs are just great!!
I never have to worry about backups (as long as you have a good off-site backup of the proxmox setup)
Using VMs separates the different services and makes managing the Linux machine very easy. Proxmox has a great web ui and gives you lots of options for the future!!
Proxmox is nothing more than a hypervisor. Yes, each VM is a VM. The hardware is virtualized, and you can run Windows, Linux, FreeBSD, etc as a VM. You can have as many services as you want in each VM if you like.
Proxmox (Debian) runs on the direct hardware. The kernel INSIDE the VM is whatever you decide it is.
Proxmox also does Linux Containers (shares many resources with the host), but this isn’t like Docker. You can install whatever services you like in your container.
just like as @flamingm0e explained.
Proxmox runs on the hardware (proxmox is essetially a debian system).
VMs can have their own kernel and everything (you can run any OS), and the other method is linux containers where the container shares the kernel from the supervisor (proxmox) and some other recources but has its own part (similar to docker containers somewhat).
I use Proxmox mostly with VMs:
Webserver for running Apache Proxy for HA and some online picture album for the family and my personal Nextcloud.
Plex Server
Another VM for networking stuff (OpenSense, PiHole, Unifi Controller)
A virtual win10 for testing
A Ubuntu desktop for testing
A second Hassio instance for testing
The last three VMs are not running all the time, just when I need them.
And then I use a few linux containers for some small programs that just do a single task (zigbee2mqtt bridge), mostly thing where people normally use a raspberry for.
But like I said above, for me the best part is the backups and snapshots of all those machines and the ability to go back in time with any of the machines if something breaks…