Firstly, I liked this finale conceptually and thematically. I'm just struggling with Farouk's transformation. I don't know when this happened.
Now, it's been obvious to me for a while that he sees David as his son and has the same desire for family and love that David has. But I always interpreted that emotion as being one of possession and control. That he wanted David to be his, in the same way that David wanted his cult kids and Lenny to be his. And in the past we see a Farouk who essentially has the same cult-style children setup that future David had and I can't see that kind of symbology as being an accident.
And yet we're somehow meant to believe that Farouk has learnt the finer art of self-sacrificing love along the way? When?
He's shown absolutely no evidence of it before this; just a desire to own and control David and prove his dominance over him.
The whole thing kind of smacked of Farouk teaching David a lesson in non-violent conflict resolution through empathy and... what??
A better ending would have been either David and his father defeating Farouk finally in the astral plane or, as others have said, a solution that involves David not being to hit a reset button on his life. Because it makes it seem like he was right - none of the deaths mattered because they got washed way.
At first I was the same but then I realised this is better. We ended on the potential of a better future; freed from external influences. Baby David's life is Baby David's to either succeed at or fuck up - and this applies to the other characters too. Which of those we get doesn't really matter because it's entirely on him.
There is always a tension between justice and reconciliation when resolving a conflict. In this case, they were emphasising the need for forgiveness and reconciliation in resolving a conflict and... they're right of course... but there's a reason why conflicts often never get resolved. People are hardwired to want at least an appearance of justice.
In fact, nobody in this really atoned for their crimes. Both David and Syd remained convinced to the end they were solely victims and refused to acknowledge any point at which they were also perpetrators. But I guess that doesn't really matter when this timeline never existed.