I never tried advanced things with "Hey Google" but it always gets the basics right for me:

"go home" opens maps app with a route to my home.

"alarm in", "alarm at", "what time is it?" works well too.

In fact I'm afraid they'll break it by shoving down Gemini.

Alexa is the same with basics, works well for me with "reminder in X hours", "reminder at 10am on every workday", "alarm at", "play The Strokes", "add coffee to the list" (groceries)

Alexa is really bad with any advanced stuff I've tried. Didn't try with "hey Google"

Any other basics that work?