Most monitors for viewing images do not show colors and brightness correctly. And even calibrated monitors might have problems, not able to show the full gamut of colours and shades of grey or they were calibrated to a wrong candela target (too low or high).
There is not much we can do, not everyone needs a monitor calibration system.
Colours, make sure your browser supports colour profiles, some browsers do not show the correct colors (hue saturation), which results in oversaturated rendering. Make sure that the brightness level of your monitor is correct, the test strip below shows a limited number of shades of grey.
Can you see them, from dark to bright, do you see a difference between the wegdes? If not, adjust your monitors brightness control until the wegdes show a reasonable distinction.
I put a lot of effort in the creation and development of my photographs, so this is important to me. Thank you.