I believe you are describing a single-tile wang system, but the smallest area you can draw with my autotiles is 2x2 tiles. I'll never make a single-tile system because it requires a ridiculous number of tiles:
This is an unnecessary level of control, in my opinion. My tilesets are primarily inspired by Secret of Mana and Trials of Mana, which didn't use this system.
You can certainly use my tilesets just fine with Godot, you just won't be able to paint with a single-tile terrain brush (RPG Maker users have a similar caveat). I recommend using Tiled, then importing to Godot, or just placing your tiles by hand within Godot, as you won't find many creators going to these lengths for an autotile.