My neighbors loved their new remote control options but had several feature requests (doesn't that always happen? :)) - I must say that they were very polite about it and not acting entitled at all, so I was motivated to develop the system even further :)

• I tweaked the web UI a bit so it could be added to the Home screen of any Android/iOS device, would support auto-login and behave as a PWA. This brought the experience on iOS very close to a native app
• I added Apple HomeKit support via Homebridge - for those who wanted it I just installed the Homebridge server on their existing RPi and told them to optionally get a HomePod as well to control the apartment via Apple's Home app outside their home WiFi.
  How I did it: A simple script generates a Homebridge configuration file for each apartment (which varies by the amount of lights, blinds, power sockets and HVAC options) which can then be applied to the default Homebridge install. The plugins I used: homebridge-http-switch, homebridge-http-multiswitch, homebridge-http-temperature-sensor, homebridge-http-humidity-sensor
• I added Google Assistant/Home voice commands using IFTTT - just needed to code a simple service that parses the voice command received and matches it to a name of the light/blind/power socket.
• I also added Amazon Dash button support which I enjoyed for a few years until Amazon decided to remotely brick all the buttons :( - I then switched to Shelly Button 1
• I extended the original Android app to support dropping icon shortcuts to the home screen - touching them triggers an action without displaying anything on the screen so it's a quick and easy way to control your apartment

With so many new options available, everybody got what they needed and it seemed nothing could be improved further. Or could it?