People are paying $1000+ for Pixel phones. I think that should cover the cost of an alarm app.
The hidden costs of apps Google gives you for "free" is probably above $1,000. I guess the majority would give away their privacy for that amount these days.
I wish there was a SaaS application which provided assistant capabilities by a monthly subscription. You can see all the data stored, you own the data the service just creates models to enable use. And you could stop the subscription which wipes all the data including the models. Perhaps some startup founder is reading this?
Making an Android frontend seems easy enough.
(You can also DIY by installing Home Assistant and Snips on a Raspberry Pi or other computer)