Dark shadowy patches along the bottom of my MacBook Pro screen

If it's a 2016 or 2017 13 inch, search 'flexgate'. That's the name the display cable issue got, and it describes this exactly: shading along the bottom that looks like stage lights and gets worse as the lid opens wider.

Take a screenshot and look at it on another device. If the patches aren't in the screenshot, it's the panel or backlight, not software. Dark uneven areas along the bottom edge are typically the backlight. Some MacBook Pro models had a known display cable problem that showed up exactly there and got worse the further you opened the lid. Which year is yours? Run the serial through Apple's coverage check and ask Apple or a repair shop about any display service programme before you pay for a screen. Also rule out the boring one: keyboard marks pressed into the coating look grey in some light.