My "HA" setup is really driven by Zigbee2MQTT -- most of my lights, devices (light switches, washer, dryer) and sensors (temperature, motion, doors/windows, water leaks) are all random Zigbee devices that Zigbee2MQTT does a wonderful job talking to, without any need for vendor software or services.
I happen to use Node-RED for automation -- this is the easiest part to replace, it could just as well be Mako, pyscript, AppDaemon, NetDaemon, or plain Python scripts talking to the MQTT server.
What I can't easily replace from HA is the nice UI, both over the web and as an app (same thing really). I guess Mako makes it possible to hack together a web interface, but it's a lot of work for a poor result when compared to what you get with HA (or OpenHab) out of the box.
I would love to find a simpler, MQTT driven "HMI" app for both web and mobile, completely disconnected from the logic behind.