I know it's not every day that it's suitable to report a problem with running an app in Windows Subsystem for Android to Android app devs, but since there are no known good native ruler tools for Windows desktop, I decided to give it a try to report it:

It doesn't appear to me at the time of writing that the app is able to acknowledge calibrations higher than circa 40mm, and always rounds down to 40mm if set to anything higher. This becomes a bit of a problem when the line in WSfA is in fact 70mm on most computer setups I've seen.

Ruler app version: v1.1.1
Android version: 12
Device: Self-built PC running Windows 11 22H2 and a customised WSfA version from June 2022 (I've forgot which repo the build came from, and it seems to be incompatible with being updated from the MustardChef builds), but I remember this was a problem on stock Microsoft official WSfA in 2022 too.

If you fellows need any more info or screenshots/photos on this, feel free to give me a heads-up.