I badly wish that I could get (competent) home assistants with at least somewhat customizable activation keywords. I understand why it's not customizable. They build it into the hardware so that it doesn't have to be truly listening all the time. But I'd love at least some options to buy versions that have different phrases.
For me, I just want something that references some pop culture AI (eg, HAL, Glados, etc). I especially don't like Google's approach of saying the freaking company name.
There are locally hosted (not connected to internet) home assistants. They take more setup but are a lot more customizable, especially the open source ones.
I've hosted one on a raspberry pi and it took at most a second to process and act on commands. Basic speech to text doesn't require massive models and has become much less compute intensive in the past decade.
google is completely capable of adding custom wake words, they already have a feature that lets you set up custom words that skip the "hey google" so you can just say something like "lights on" and it activates a routine that does that.