All these boards do work. It isn't really a hardware problem.
(well some do have issues with their backlight control circuitry)
The problem is software and the most common issue is the libraries and the fact that not all the boards are wired up
to the LCD modules the same way so getting the proper library and more importantly the proper
lcd library constructor for the library is very important.
Often the maker of these low cost boards, isn't supplying a working library or examples
that are properly configured for their board.
For PCF8574/PCF8574A based boards, (which both of the two above boards are), I recommend using
The reason being is that it works. Plus the constructor for the PCF8574 chip allows configuring
any wiring. So that means as long as you fill in the constructor properly to match how the LCD module
is connected up to the PCF8574 chip, the library will take care of the rest.
This library has quite a bit of testing on it and has several fixes in it for initialization and
for other sized lcds that are not in the majority of lcd libraries out there.
Not sure about the ywRobot pin wiring but I have a pair of of "mjkdz" boards that look
like the ones in the photo and wrote up some information on how it is wired up
which can be used to fill in the lcd constructor for
the i2c device layer in fm's library.
See attached note for information on the "mjkdz" board.