does non harem dating sim mean i can only do one girl and then i would have to replay the game to go for a different one?
Yesn't!
In the long term, only one girl route yes. But in current 4 episodes (and even further in future) you aren't penalized for going for all girls. Just the longer you are undecided (and going for everyone), the more points you will lose, and odds of losing content with a certain girl will increase.