Build mode Half tile use & split level homes

I really want there to be a way to use the half tiles in build mode for the walls. If there is a way and I’m just dumb can someone let me know. I’ve been trying to build an entire game of just my real life so my apartment, my family home, etc. and the proportions are extremely off because I’m not able to place a wall on half the tile. Also, it would be nice to have better platforms to make split level homes without having to watch a million tutorials on how to cheat the system with it. For instance, my family home has four steps to get to the 1st floor but you are able to access the basement from the ground level and the 1st floor because the stairs go down from the 1st floor and have a landing wrapping around to go down into the basement. I’m not able to add this feature in the current game. Is there a way to make this happen? I feel like this would be an easy update to the base game.