Fair enough - I got it working recently but it was the hardest self-hosting install I’ve done. No way most people would succeed. Email is 50(?) years of questionable design decisions piled on top of each other so it’s become a whole world of weird stuff. Doing email should be it’s own tech specialty, like ‘devops’ or ‘db admin’ is. There’s enough depth to it.
There are a ton of email providers who are not Google, though. e.g. https://proton.me/mail. You don’t need to run it on your own hardware.
In the Homarr docs, there is this: https://homarr.dev/docs/widgets/iframe/
Towards the end there is a link to https://github.com/diogovalentte/homarr-iframes which contains many examples of some content formatted nicely to fit within Homarr iframes and a docker container you can use to make a url that the iframe widget can consume. They used Go which is only a little harder than Python to read.
Seems like this one - https://github.com/diogovalentte/homarr-iframes/tree/main/src/sources/changedetectionio - makes a request to a JSON api, for example.