It's clear that the Nabu Casa Inc. people, who also happen to be the Home Assistant project leaders, are focussed on making money over making well engineered software.
It's clear that Paulus created a free home automation product and developed it for 5 years. For free.
In 2018 they started a fund raising system which also helped provide secure remote access for those that don't know how to do it themselves.
I'd say they are focussed on making well engineered software over making money.
Flash with ESPHome? Not that I'm aware of (but would be nice to know)
Edit: just found this: Smart Bulb (9W/RGB+CT) - Preflashed & Preconfigured
I'm happy with the Shelly bulbs, they work without internet shenanigans and can do MQTT, etc...
I have used Pi Zeros and ESPresense for prsence detection... seem to work ok, but if you're wanting to do room-level detection, (ie who's where), then that seems to be really difficult to tune the sensitivity