I've got enough of the maze format reverse-engineered to make use of it. The mummy maze is maze10.maz.

First things first, hugging left will most likely give you the most coins, but one of the slowest routes.

Quick warning, this assumes that wall order is not a thing. If you run against an outward-facing corner, if you're rubbing against the side that is later in the list, you can "snap" ahead a bit... or behind if it feels like doing that because all walls in the mazes are double-sided. (Yes, every wall in a maze is in an ordered list of walls.)

Here are two runner-ups for consistent fast routes:

• Left, go until wall, left, go until wall, left, go until wall, left, go until end. Easy to remember.
• Left, go until wall, left, go until wall, RIGHT, go until wall, left, go until end. Looking at my maps this should be ever so slightly faster, UNLESS the wall order is in favour of the other one.

This one I think is the actual fastest consistent route:

• RIGHT, go until wall, left, go until wall, left, go until end.

And here's the fastest route if the stars align correctly and enough people spam BlessRNG in chat:

• Manipulate the mummy to get out of the way at the first junction, then get in behind where the mummy was. Go until end. Yep, there's an exit there too!

Enjoy.

Great work on the run! I had no idea about the exit behind on the mummy. Thanks for playing!