https://cacaoeditions.com/your-cameras-and-lenses-are-crooke...
Lenses themselves often also have tilt from 50-200 microns, which you can also measure and shim.
Also, after skimming through the second article, I had to wonder: if the first article found dropped cameras and other problems in flange-to-sensor data, wouldn't they also find mount tilt if they looked for it? Given that drops don't usually impact the camera exactly orthogonal to the plane of the flange, it seems like flange-to-sensor distance won't be their only problem. But maybe replacing the flange on these also fixes any tilt. Then again, there may be damage that affects the tilt but not the flange-to-sensor distance.
Someone posted technical illustration of the Denz measuring equipment, and I wonder if they couldn't make a similar apparatus with 3 or 4 pairs of measuring beams (or 2 in a cross pattern), thus it could measure the distance at several points and thus the parallelism of the 2 planes.