While you can run HA as a container. I think it's a mistake - Its more complicated and has reduced features.
I would instead recommend people use HAOS instead - either running on dedicated hardware OR as a VM. Just dont run it from an SD card if you go down the Raspberry Pi/SBC route - it will kill the card from IO cycles.
I have an IOT VLAN on my network that all the IOT bits sit in, including WIFI devices. What internet access it gets (if any) depends on the device profile.
I tried splitting things up into multiple VLANs but a whole lot of things assume just a flat network, so things stop working if you get too fancy.
I go the container route, and have only had one issue: allowing HA to access my system's Bluetooth adapter. I had some ESP32s lying around, so I used ESPHome to make a Bluetooth proxy, which solved that issue.
I don't run addons though, which might be part of it.
What router and associated configuration software are you using? I have a Eero mesh network that leaves a lot to be desired for a fiddler like me.
> While you can run HA as a container. I think it's a mistake
Just because you CAN run something in a container, does not mean you should.
HAOS exists because it is a docker run time. It is a whole ecosystem, not just the home assistant software itself.
> it will kill the card from IO cycles.
It might not. I have a Raspberry Pi 2 that has been running a weather station for over 12 years, and it has been on the original SD card. I have other RPi's doing dumb things around the house and I have never had an SD card failure.
YMMV and all that.