Programs? I meant kernel and drivers. I don’t even need to open an app. My ASUS laptop with a 4090 steadily fails with an LG 40WP95XP with anything else than 100% DPI. My previous ASUS N552VW failed quite often on kernel level because it couldn’t handle the built in 960M, and it definitely couldn’t handle at all my older ultra wide monitor (I don’t remember anymore what was the model exactly).
Please describe "failure": I've had a Sony Vaio Z with switchable Intel/Nvidia graphics in 2009 before Optimus (though that did require some tinkering), but had GTX 960 and GTX 970 (actually still do) in a couple of computers, along with an integrated Intel and AMD GPUs in a bunch of laptops.
Note that kernel is totally unconcerned with DPI in general: it only cares about physical pixels and reports physical dimensions to apps — if scaling caused kernel level issues, it might be related to proprietary driver issue (they frequently lag in Nvidia's case).
I never used ultrawides myself, but if the monitor did not report proper "timings" and available resolutions, you might have needed some manual tweaks.
