i worry about this.im not convicned tunnels are the way. if something goes sideways, how can you back that thing out. in typical boring applications you have tracks to remove material. we gonna ship tracks to mars! i think a remote control bulldozer is a much simpler solution. it cna move slowly, it can recharge. it can dig slowly and back itself out of problems. plus we can inspect the trench with a drone before we land starship in it, or dop payloads into it.  alternatively we could make specially constructed remote landing starship habs. land it in the trench, drop it to its side, and bury it. im not sure we could drop it to its side.
Canada