FPS decreases significantly in Vulkan api when turn on the new Steam performance monitor overlay

[ColdDown]

More detail, Just showing FPS on overlay cause no problem, while showing more stats on overlay, fps decreases significantly.
It only happened in Vulkan api as I tested.
Notice the top left corner in video.
View attachment Deadlock_replay_2025.06.30-06.48.mp4

 

[ColdDown]

After 07-04-2025 update, I tried the overlay again, and fps is higher than before, but still small decrease, I am not sure whether dev fixed it or just my pc sucks