New to Homey. Missing features in Homey and non-working apps / integrations

That’s indeed the case. You’ll find several topics ons this forum in which users are requesting adding the dashboard functionality to Homey’s web app, like this one: [Request] Web interface. That also includes the response from one of the Homey founders on the decision to make Dashboards only available on mobile:

And

But, that was the state end of 2024. You might want to add to that discussion or reach out to Athom with your suggestion (via http://homey.app/support/).

There are alternative dashboard solutions though that work via a web interface (but not via the Homey mobile app). One of which I want to highlight, as it is in continuous development and offers many visualization options: Dashboard Studio. It also has its own forum topic: [APP][Pro] Dashboard Studio - A completely free-form dashboard designer. It does require some effort in setting up, though I onderstand the developer is adding more and more ready made components.