Reduce the Amount of All My Brush Adjustments at Once?

First click the little down-facing black triangle near the top-right corner of the Adjustment Brush panel (shown circled here in red). This collapses all the normal sliders down to just one Amount slider (seen above middle), and that slider controls the overall amount of all the sliders at once. Here, I’ve dragged it over to the left, lowering the Amount of my changes, and then when I click on that triangle again to expand the panel and show all the sliders again, take a look (above right) at how much lower all the slider amounts are now, compared to what they were originally (above left).