I don't think he would have any issues with the comfort of living in Saudi Arabia, he would have the red carpet rolled out for him. Mo Salah is a muslim, he would obviously feel at home in Saudi Arabia with the welcome he would get there as well as the muslim environment. Furthermore, he wouldn't be on the end of racist abuse in Saudi Arabia, which he has been subjected to in England. However, for Salah, there is no real good enough reason for him to move right now. He is playing at his peak at one of the best clubs in the world in the best league in the world. Salah is already being paid a bomb by Liverpool, so moving to a lesser league, where they pay good money, is not a big incentive for him right now. Would it be a possible choice for Salah in maybe 2 years time to move to a club in Saudi Arabia when he's probably just past his peak? Yes, that seems much more of a probable idea.
I agree that the abuse that Salah got for celebrating Christmas, was not on, just as I condemn the racist abuse that Salah has received. But then again, I do not follow a religious doctrine and so I don't care what a muslim like Salah celebrates, just as I wouldn't care what a Christian like Giroud celebrates, but religious people usually have a differing view on such things to me. One thing is for sure, if Salah moved to play in Saudi Arabia, he wouldn't have to put up with the racist abuse that can be seen in the following videos: