Shlink has API Key authentication. Why does a front end and backend make it a con?

Have been using Shlink for quite a while and it's a nice project

So if I host my data on Google Drive and encrypt it and tell no one, that's selfhosting?

Welcome to the Internet. Check out Crowdsec and WAFs

Well scraping your app is not self hosting. Any reason why you don't provide your Git repo if you're ok with people downloading your source?

How do you self host your app?