I think you’re probably using Home Assistant OS. Home Assistant Surpervised is where you first create a Debian 10 VM and then import the Home Assistant docker image as per this guide https://community.home-assistant.io/t/installing-home-assistant-supervised-on-debian-10/200253
If you go to Configuration → Info → System Health in Home Assistant you’ll see what you have.
Yes and if you look at the VM summary in Proxmox your RAM usage will constantly increase until Proxmox reports that’s its using all of it and if you give it more it will report that it uses that too. Is there a reason you have given it 6G?