Starter/flywheel

Hey happy holidays! I have a starter and fly wheel problem. The gears are stacking up on each other cause oh an awful sound! And won’t ultimately engage the truck to start. I’ve tried to shim it and seemed to work for a week then started acting up again. Got a new starter recently had a shop put in the new flywheel and they still had the same problem. Started costing too much. And need some help! Check out the picture! It got stuck in the out position with no shim. Put a shim in and is still acting up any ideas?
Thanks in advance!