Welcome to the series!
Like you I bought SH5 on the faith of it being better then the others. BIG mistake especially at launch price, however after modding the game to Davy Jones Locker and back, I am actually enjoying the game now.
That being said, I still believe Silent Hunter 3 with GWX mod is 10x better then SH4 and 5. Granted it is very dated graphically now, but who plays the SH series for the graphics?