Creating a vlan for proxmox vm

Hello everyone, first post here.

I have a WRT3200ACM running OpenWRT. I also have a TP-LINK TL-SG108E switch on Port 3 connected which my Proxmox server is connected to.

My goal is to have a separate vlan in OpenWRT to isolate my vm (in this case a vm for torrenting/downloading).

After reading several guides and posts here, I was able to get OpenWRT running with no problems as well as setting up my switch to get internet access.

I have some questions:

1- What would be the correct configuration to make a vlan in OpenWRT to isolate this one vm? (maybe others in the future).
2- Does having a managed switch in which I had to configured vlan to receive internet complicate things?
3- There other vms running in Proxmox who won't need a vm. Would buying a separate nic for vlan traffic make things simple?

Below is what I configured so far with vlan 3 being the new configuration. If someone can point in the right direction I would greatly appreciate it! Thank you!

Avoid combining untagged and tagged vlans on the same port. Don't use DHCP protocol on the new interface, use static.

No, if you configure the vlans properly.

I don't follow you. If you can configure vlans, it doesn't matter how many you'll configure. The overall throughput will be 1 Gigabit of course.

Thanks for the clarification. If using static, do I need to fill out any other parameters? Also if configuring the vlan on port 3 only, should I just tag eth0 then leave everything else off? Port 3 is where the switch is connected but there's other devices that don't have the need for vlan3.

IP and mask are the bare minimum.

eth0 must be tagged, otherwise there is no communication to the router.
LAN 3 port currently is untagged to vlan1. If the switch is managed and you can configure vlans, then you can have both vlans 1 and 3, better both tagged. If the switch is unmanaged then use only one vlan untagged.