I found the Autotile feature in Godot for working with TileMaps.

The tilemap that i have is actually not compatible for creating an autotile, i had to modify the original tileset to support the mandatory 2x2 bit mask.

Original

Modified for autotile

added more tiles to fulfill the requirements for 2x2 autotile

for a 2x2 autotile, here’s how the bit mask is set. notice how every permutation of on/off exists

Result

More resources

AutoTile intro tutorial