Premiere Pro Preview Render Latency Issues

I'm struggling to resolve preview render latency issues in Premiere Pro and can't seem to find a working solution. The CPU isn't being used at all, and the GPU decoding usage is inconsistent. I'm working with a small 10-second clip at 1920x1080, 120 fps, 8-bit, 4:2:0. Despite updating all my drivers and using the NVIDIA Studio Driver, the problem persists.

The preview playback randomly fluctuates between 5–120 fps, but it mostly stays around 5–30 fps. This happens even with the playback resolution set to 1/4 and without any effects applied.

What I've Tried So Far:

• Clearing the cache
• Reinstalling and updating drivers
• Creating proxies
• Resetting preferences
• Switching to After Effects (same issue there)

System Configuration:

• Processor: Ryzen 7
• RAM: 16 GB
• GPU: RTX 4060 Laptop