MCP4822 not giving output as desired
The first function is a little confusing, whereas on the second initialization you don't wait for the transmission to end but seem to turn on SPI interrupts. What is the handler doing?

In the second function you don't wait for the end of the transmission and I also don't see the raising of DAC1CS/DAC2CS.
Note that if you raise CS before 16 bits have been transferred, nothing happens.
If you raise CS but LDAC {is high nothing happens|floats nothing may happen}.

I assume you have the LDAC pin grounded.