@User: I wrote qrouter and made a fundamental assumption in it that route pitches are always specified to be able to put a via down without generating DRC spacing errors to adjacent routes. Later I found out that "high density" rules do just that. Which makes qrouter/qflow completely unsuitable for the high-density standard cells. To make matters worse, X-Fab went and deprecated all of their standard cells except for the high density ones. Fortunately SkyWater is supporting the non-high-density standard cell libraries.