Hey Rick ! The novel is kinetic, meaning no choices to be made, just a story to read and hopefully enjoy.
But yes, there will be a harem that will develop itself as a close group, as the story goes on with new characters too. ( I will not say how many to not potentially spoil parts even though it is just a number )
There will also be NSFW with other quote on quote SIDE characters that won't specifically be a part of the main group but will still play a role within the story.
Won't ever have NTR, nor any sort of implications for other characters. The story will revolve around the MC always.