twiddler

"The twiddler kept adjusting the settings on the device."

"As a twiddler, he found joy in making small changes."

"Everyone knew him as the twiddler of the group, always tinkering with things."

"She began to twiddle the knobs on the radio until it worked."

"He likes to twiddle his pen when he's deep in thought."

"They sat together, twiddling with their phones during the lecture."