To provide a bit of context, we have currently configured an AppleTV 4k, 4 HomePods, Hue bridge, with lots of hue lights, 1 hue motion sensor and a few hue switches.
I configured everything using the home app on the iPhone, but I was always disappointed with how simple the options were. For example, my dimmer switch has 4 buttons, but I have the option of using 1 button to turn on / off a light, I have to set 2 separate buttons to do this, seriously impacting the amount of light that a single switch can control. So far, I thought this was a limitation of Homekit, but I learned that it is a limitation of the ios Home application. I came across another application that allows me to set more complex options for these controls, including long presses, etc. (these are not available in the home app, but they work fine with my homekit devices.) Now, since I don't have to have this third-party application open for automation to work, obviously storing the settings in the home somewhere. (Btw, I've always wondered where these are stored. Is it on iCloud or my active homeekit hub, ie: homepod or appletv, or is some storage shared with my available hubs, etc.)

However, the third party application I used is very buggy and very difficult to use. I wonder if Homekit really is capable of much more advanced automation than what's available in the ios home app, how can I reach its full potential? Is there an API endpoint that I can access somewhere or is there an application that allows me to configure it?