Aurora R10, FPS drops and stutters in 2D applications

I'm struggling with 2D performance on my Alienware Aurora R10 with GeForce RTX 3060 Ti.

Sometime within the last couple months, 2D applications have started getting stutter FPS. Streaming video drops frames; Discord and Slack lag as I type; scrolling through something like a Steam store page tends to pause and lurch. 2D games -- I've been testing using the busy survival shmup HoloCure -- range from slow to unplayable, with drops down to 15 FPS even with very little onscreen activity.

3D performance is great! Any 3D game I fire up (recently FFXIV, Borderlands 3) works brilliantly.

I can improve performance in browsers and Discord by disabling hardware acceleration. It's not a 100% fix, however, and doesn't help in applications that don't provide that option.

Things I've tried:

• Applying latest Windows patches, graphics card drivers, and firmware updates
• Uninstalling the most recent Windows Update
• Rolling back to previous nVidia driver versions
• Installing nVidia "Studio" driver instead of "Game Ready"
• Removing nVidia's GeForce Experience app
• Upgrading from 16GB to 32GB of RAM
• Installing Dell SupportAssist and running a hardware check (it fails)

Today I found a strange workaround: if I install GeForce Experience or MSI Afterburner and commence "automatic performance tuning" (GFE) or an "overclocking scan" (MSI), performance in 2D apps becomes smooth and pleasant while the scan is running. As soon as the scan concludes, performance goes back in the toilet. Any ideas what I could do to get smooth 2D back without, like, running an overclock scan whenever I want to watch a YouTube video?