An intuitive and easy way to find max. raster pixel value is to use a color ramp with dynamic stretching so that when you zoom in, you always see in which area the max. pixel is located. Zoom in until you reach pixel level.
As you see in the following animation, it's just a few seconds until you're at the max. value pixel (see below for detailed explanation).
Unfortunately, I can't upload gif's larger than 2MB, so I had to reduce image size, but the principle should still become clear:
set layer rendering style to
Singleband pseudocolor and select a color ramp with good constrasts, like Viridis. Expand the
Min/Max Value Settings and set
Min / max >
Statistics extent to
Updated canvas - like this, when you zoom in, you'll always have the maximum color range from dark violet to yellow can can immediately see where to highest points are located.
Updated canvas means that min/max values used for the rendering will
change with the canvas extent (dynamic stretching).
First, show the whole extent of the layer, than zoom into an area that clearly contains the brightest (yellow) spot (screenshot 1). Zoom in more and more, always to the area containing the brightest spot (screenshot 2). When you reach pixel level zoom, you easily see which pixel is the brightest one. Clickin on it with the identify tool confirms: this pixel has the same value as the max. value in the raster (last screeshot).