Well Google phones started out as bare bones Android as you could get and they have matured a little. It's still a lot less frills than most other devices. I have the 3XL and the S10+ and it feels to me like they have both headed towards the middle with Pixel still closer to stock Android.
It's sometimes hard switching phones because I forget which one I'm using and the gestures throw me off. Unlike like when I use my iPhone and know where I am.
https://gizmodo.com/samsung-one-ui-vs-stock-android-whats-the-best-version-1833556973
What caught my eye was this:
We’ve been putting One UI through its paces on a Galaxy S10e to see just how well it works versus the stock-Android-with-a-few-little-twists that Google uses on its Pixel phones
Now it's down to how many angels can dance on the head of a pin. Where's the line between "stock-Android-with-a-few-little-twists" and "manufacturer skin"?
There really is no such thing as stock Android. Every manufacturer, even Google, puts its own skin on things.