Replying to my own post in case anyone’s following this (still too new to Lemmy to know if that’s a thing - guess I’ll look into it after this).

Apparently, Moto may be working on something that fills this need. The promo video in this article only demonstrates things I think Google Assistant might already be capable of (or maybe slightly more), but the article states what they’re working on involves using apps on your phone to do things rather than just being a microphone and speaker for stuff that actually happens mostly on Google’s servers. Crossing my fingers that includes doing what I want rather than just being focused on buying things as demonstrated in the teaser video.

In the meantime, I’ve stumbled across the fact that Google’s built-in TalkBack feature has support for keyboard shortcuts. This likely means I can use a small handheld Bluetooth game controller along with an app to map the buttons to the appropriate key presses in order to move around the screen, and thus control the Android device without looking at or touching it. I’ll likely test this next weekend & report back if anyone’s interested.