Frame size information avaliable on the Internet in numerous articles is mostly about MTB or road bikes, with regular frames. Can you help me calculate the right frame size for a cross bike with compact frame?

My bike is built with the frame of the Merida Crossway 8900. It actually feels a little uncomfortable at long distance ridings. I guess the frame size is not exactly the best for me, could you help me check this?

That frame is avaliable in 46, 48, 52, 55, 58 cm sizes.
My height is 186 cm, the length of my inside leg is about 90 cm.
Which size would you offer for me?