The fastest way to reduce random trial is to reverse-search from the target tile and design required stoppers first.
Most missed solutions happen because players push robots forward without a landing plan. Reverse search starts from the destination lane and asks where the final stop must be.
When you begin with the final line, mid-path decisions become simpler. You only build helper positions that are required for that final approach.
Step 1: mark the final arrival lane and identify which side entry is possible.
Step 2: find which robot or wall can become the last stopper.
Step 3: solve how to place that stopper with minimal extra movement.
If your target robot reaches near the goal but cannot stop, your stopper was never planned. Back up one move and rebuild with the stopper rule first.