Since the stem is hitting against something at the bottom of your steerer (probably the brake bolt), you'll never get more insertion. By the way, I have never seen a butted steerer.

Because the Technomic has so much rise beyond the steerer, the leverage on its connection are greater. It therefor needs to extend further into the steerer, which explains why you're seeing the minimum insertion line. By cutting the stem down, say, an inch, you will lower the height and reduce the leverage. In a sense you'll be converting it to a "semi-" Technomic having more rise than a normal stem but less than an uncut Technomic. I would recommend cutting at least enough to bury the minimum insertion line.

You might have to extend the threading on the quill binder bolt.

A safer, less invasive work-around would involve purchasing a quill converter and a threadless riser stem. There'd be no cutting and machining and no question about getting a strong interface between your handlebar and steerer.