Consider simply tapping the hole to the next larger metric bolt.
Apply some heavy grease to the tap and back out the tap frequently to remove the aluminum-fouled grease. Apply more grease and continue. There should not be much in the way of aluminum chip dust as the original threads are now long gone.
If you have concerns, do not rotate the rear wheel before you flush the final drive with some kerosene once or twice and refill with gear lube. Any tiny flake of aluminum will not bother the pinion and crown gears.
Use a new crush washer each time you remove that small bolt and avoid gorilla-torque. Unless you are seeing gear lube dripping off the final drive case, there's really no need to continually check levels. I have not removed that little bothersome bolt in years. I simply drain the oil and refill with the spec amount and ride on until the next scheduled maintenance.
Be cautious with the front fork lowers, too. Another PITA waiting to happen.
