I agree with you completely. Devices that rely on external servers are not OK. My house's automation uses IoT devices that host their own servers, and/or communicate with those locally that do. I had to build them myself since no company I could find offered anything like this. I'm not a snowflake either, other engineers have done the same.
Currently, IMO, the only reasonable solution to home automation is to do everything yourself, from absolute scratch. Commercial solutions are a combination of insidious spyware and stuff that will become useless when the company becomes acquired, dies, or gets mad at you and shuts down a server.