Performance degradation in unmodded Bedrock world despite low CPU/GPU/RAM usage

I am experiencing noticeable lag/stuttering in an unmodded Bedrock world, even though system resource usage remains low. The world previously ran smoothly under the same settings. RAM usage stays around ~3 GB, GPU usage is well below maximum, and overall CPU usage is ~20–30% (no core at 100%). Despite this, the game exhibits slight but persistent lag.

The world has never had mods installed. I use world copies to test mods separately, but the affected world has always remained vanilla. This issue appeared without changes to the world itself.

Steps to Reproduce:

1. Open an existing, unmodded Bedrock world (approx. 363 MB in size)

2. Use render distance ~30 chunks and simulation distance ~8 chunks

3. Move around the world normally

4. Observe intermittent lag/stutter despite low system utilization

Expected Result:

The world should run smoothly, as it did previously, given low RAM usage (~3 GB), GPU not at max, and CPU not saturated.

Actual Result:

Slight but noticeable lag/stuttering occurs, even though system resource usage remains low and unchanged.