So I'll just set it to Manual keep at it.
For a "Set it and Forget it" setting, choose "P".
Actually, the easiest set it and forget it is to set the lens to MF. Turn the focus ring to the shortest distance, but do not hit the end stop. Set the lens to Av mode, so that you can specify the Aperture. Dial in an ISO value, ranging from 100-800, depending upon the amount of available light.
Now focus on a subject by moving the camera forward and back. Of course, this does not work if you want to perform any focus stacking. But, it works fairly well with a tripod, especially with an Arca-Swiss clamp on the tripod head, because you can slide the camera forward and back a little smidgeon if you want to.
"For a "Set it and Forget it" setting, choose "P"."
You can use the same move the camera in or out for focus and still use the more friendly P mode.
You could use P mode, except you do not have direct control of Aperture. The OP has been using M mode, anyway.