The fact that a viewer is left with questions, or at least things to ponder over, is a large part of the ‘point’ of the narrative!
What was the point of Paul Mescall's character?
I’d say the point of both the waiter and the caretaker was to show how useless Leda was at human interaction. She was constantly wrong-footed because she misjudged what other people meant by their actions.
What happened to her husband?
They broke up.
What happened to her daughter?
She had two daughters.
Was she talking to both daughters on the phone at the end?
She was speaking to one, iirc.
What was the point of the 'gangster family'?
A constant atmosphere of threat. Which put Leda on edge and meant Nina appeared vulnerable and trapped.
Why did she steal the doll?
Because she was partly held in the moment when she abandoned her daughters. She was, to me, trying to reprise the unconditional loving care she deprived her daughters of. But also getting revenge on the Italian family for disrupting her calm holiday.
Did she die at the beach?
No. It might be said she was cleansed / re-born by her night on the shore after the ‘punishment’ of the accidental stabbing.
What was the relevance of the female hiker she kept hugging?
Ok - there’s probably a connection to Dante’s ‘Paradise Lost’, which I will have missed - but essentially, she had been doing her best to be a perfect mother because that was what she believed the world … needed. The hikers showed her the world was already broken - and no one had died - so there was no requirement for her to continue the facade.
I’ll probably have better answers tomorrow - still musing on it!