ACR 17.4. I already reported that copy/paste is the only way to make a change to denoise amount, typing into the amount field or moving the slider doesn't work.
Even then, multiple image settings cannot be changed.
Load multiple images into ACR
Select all, apply denoise
Copy/paste a new amount into the denoise amount field
Expected: Denoise amount will be changed for all selected images, LIKE EVERY OTHER ADJUSTMENT IN ACR
Actual: Nope. Only the first image will be changed. EVERY IMAGE MUST BE INDIVIDUALLY UPDATED.
ACR on Intel Mac, 15.5 Sequoia.