While I can't tell your exact requirements, it looks like you may be over complicating things.
Firstly, how much traffic do these sites handle, do you even need such a bespoke setup? It's worth noting ...
if all of these PC's that will only be used by one person were
connected to the network, how much bandwidth will be eaten up as a
Probably not enough to even be noticeable unless your users ...
If you are using cloudflare here is a terraform module you can use.
just update your ALB security group ID here