A Restart with Harem System?

A young man named Alan died. He got transmigrated and possessed someone else body into another world where magic and system windows existed.
His life was not easy. The world was in chaos, and he died again, but that was not the end.
He kept coming back alive to the same world with a bad ending.

Now for the fourth time, he goes back 25 years before the dark ages come. Can he and his harem survive this time? And find out the truth about the secret of this world?

PS: English is not my main language. Wish-fulfillment story. Harem will be big in the future.
I don't own any base asset for Illustration that will be posted in every chapter (1-3 pic) It's open for public use. Though I set the pose, setting, and create the OC.