onwall function just for tiles?
 

The onwall function returns true if the (x,y) is on a wall tile OR on a NPC with a shape and is blocking.

Is there a function that detects only if (x,y) is on a wall tile and not the NPCs?

I know I could find near npcs and compare the distance, but when I tried that, it seemed quite buggy...

Check if tiletype(x,y) == 22 (blocking)

There should be functions called wall() and wall2() or something similar in Era's -MoveSystem, where I emulated onwall() and onwall2() functionality for two special tile types. You can probably use that as a base.

Ah didn't think of using tiletype(). Thanks!