It looks like you’re not understanding what a VLAN is. It is a virtual LAN, it’s near physical separation of traffic.
In your example, your IoT devices and HA would sit in their network. Your PCs and phones on another, reaching outside through PiHole. Your *arr suite in a third, only routed outside through a VPN. You get the gist. And then you set rules on how these subnets talk to each other in a router, like you would do if they were physically separate.