Integer scaling with CRU-created resolutions

The 3456 x 2160 resolution display on my Dell XPS 15 is overkill and causes lots of Windows scaling issues. I created a profile in CRU with exactly half the dimensions (1728 x 1080) to see if I can use that instead, with the goal being for it to use integer scaling to look just as sharp as if that were the native resolution.



Unfortunately it looks quite bad. So I opened Intel Graphics Command Center to enable Integer Scaling, but the only option it allows is "maintain aspect ratio". This must be using NN, not IS.

Interestingly, I do get options for "centered" and "stretched" in other resolutions, but selecting them fails with a "Something went wrong applying settings. Please try again" error, forcing "maintain aspect ratio" to stay selected. In the 3456 x 2016 native resolution, "maintain display scaling" is available and autoselected, and trying to switch to "centered", "stretched", or "maintain aspect ratio" all result in the same error.

On my external 3440 x 1440 monitor, integer scaling works fine, so the system is capable of it.

It seems I have two issues:
1. I need to troubleshoot why switching to any IS-based scaling on the built-in monitor fails.
2. I need to figure out how to enable IS options on CRU-created resolutions.

Any help would be appreciated.