This is why my smarthome strategy is, that everything must work locally (as in without internet access) - but can be enhanced by connectivity to the internet and cloud-services.
I use https://www.home-assistant.io/ on a Raspberry Pi 4 and I only buy devices that work locally, are either super dumb (think zibgee lightbulb) - or are either already open or can be flashed/hacked to be open.
There is a huge community around this approach on https://www.reddit.com/r/homeassistant/