Ok,
Do you have a photo with the crank installed, but the bolt removed?

I would probably remove the crank arm. Lightly grease the spindle, and put it back on. And, keep tightening the bolt if you can.

I think the crank should go about 3/16" further down on the spindle. Ultimately the bolt will be fairly tight. I do most of my personal work by feel rather than torque, but someone should have torque specs.

If you ride the bike with the crank arm loose, you risk hogging out the arm, and permanently ruining the crank arm.