I see several problems, but without more documentation I can only guess. First your soldering is poor and needs to be fixed. Second I do not see the required contrast pot. I think there are more such as it does not illuminate. You did post some nice pictures, very clear.
The symptoms you describe indicate that the LCD has power, but communications are not functional.
That is most likely due to poor connections. The header pin soldering is poor, and an obvious suspect, so go over all those joints until they are properly filled. Adafruit has a good soldering tutorial.