Pebble is the ultimate smartwatch because it knows what it is. Its a watch first and foremost, readable in any lighting conditions, waterproof, battery lasts for weeks. They made a watch first then added only the QOL features that most people need.
My only complaint is that app limitation are apollo moon lander level of bad, like 128KB code and 256kb resources. I'm not particularly versed in optimizations patterns in here, but building fun stuff is really hard with these limitations. So what you have to do is roll a "companion app" android app that does all compute on the phone and streams it to the watch but that sucks.
What is your idea of fun stuff? Code and data is cheap enough with these constraints, though fancy graphics are what will eat your budget.
Point me to your project on GH or wherever if you want me to have a look, I've optimised a lot of code in this life.
I suspect 10MB might be more friendly in the current day and age.
So all in all: it has been done.
That being said: you mention python, and I'm not sure where this is coming from. When in rome, you don't drag your favourite language throught the streets unless it is roman latin.
I can dismiss/decline/silence popped up on my Pebble without breaking eye contact with the real life human I'm talking to.
In a car, I've handed my watch to my kids in the backseat so they can control music playback. There's no accidentally closing the media app because they fat fingered a stupid teeny tiny touchscreen. Nope. Just regular buttons that anyone with functioning hand-eye coordination can use.
And unlike the Garmin Instinct, the buttons are actually ergonomic. The Instinct was literally painful as you had to contort your hand. And on top of that, the UI was totally insane. I was never quite sure how to interact with it and frequently had to experiment to do basic actions. Nothing was consistent.