Luke has been holed up in a very safe and isolated planet for years now and he didn't bother to fetch his daughter out of indentured servitude? Then presumably he thought she was dead, which is the only explanation that doesn't make him a terrible git, but that doesn't explain why he looks so grim and unhappy when they meet at the end. That's not the look of a father who has just realised his long-lost daughter who he thought was dead is actually alive. He reacts more strongly to the lightsaber than he does to her. Nothing about that scene hints that this is the reunion of a father and daughter. It reads as a scene where a talented hopeful is reaching out to a wise master who has shut himself away from the world. He's unhappy because the last time he mentored someone, they turned into Kylo Ren. There is no joy in his expression.

If she is not his daughter, this all makes perfect sense and Rey's arc for this stage of a trilogy has satisfying closure as per Maz's words that she would not find belonging with her family (behind her) but with Luke (ahead of her). At this point, she has reconciled that her family is not coming for her. She's taken charge of her own destiny and come to Luke in order to begin the next chapter of her life (and the next chapter of the Star Wars franchise).

If she is his daughter, then her arc is not 'letting go of the past' (so Maz was making shit up about not finding belonging with her family) but it is indeed of 'finding her actual family'. But then this fails because there is no closure. She meets Luke, but he's not pleased to see her and shows no sign that they're related. There are no answers. People are literally having to impose subtext that is not there in order to establish the Rey Skywalker theory as likely.

The conversation between Maz and Rey in the trailers kinda says it all to me. "Who are you?" "I'm no one." Rey is a more impressive character to be rising from total obscurity without the benefit of purebred lineage, and it's two fingers up at the villain's ideology that he's owed everything (great power, cool lightsbers, etc) simply because of who his family is. If it turns out you ARE owed great power and cool lightsabers because you're a more pure Skywalker than the next guy (because Rey gets it all), that sort of defeats the message that Kylo's sense of entitlement is misguided.