Are you allowed to push off the walls? I feel like the fastest possible mouse would be one that just punched itself from wall to wall.
https://ukmars.org/contests/contest-rules/micromouse-classic...
And even if you're not pushing off from the walls, additional wheels on the sides of the mouse could help get more traction by running along the walls.
(https://ewh.ieee.org/sb/columbus/devry/sacFiles/MicromouseRu...)