This actually sounds like what they're doing at Home Assistant.
Buy a HA Yellow or whatever, plug it in to your network and turn it on. It loads up and you log in on a web page on your phone. Install an app, sign up for Nabu Casa and get your services working outside the network.
And it'll pick up a lot of what's already on your network and set it all up for ya.
I read comments! I watch a lot of videos about self hosting services and the comments is where you find other people who have followed the video and struggled at some point. If you're lucky it's a common sticking point you're stuck on and someone in the comments has a way of fixing it.