It's not mythical, technical solutions underpin virtually everything in the 21st century.

It doesn't even have to be that complex. Self-assessment for businesses, with random (away from the border) checks and fines or imprisonment for fraud. Problem solved.

It's an infinitely better solution than your unicorn you are suggesting of finding a solution that doesn't compromise the EU's or the UK's integrity. Since violating the integrity of the EU and the UK are non-starters that only leaves a technical solution as the only viable alternative. Unless you can describe your unicorn alternative.