Proust put 2 sentences into one!!

Reader86

Not quite—it’s actually a bit sadder and more resigned than that!
He isn't thinking she will come at other times. Rather, the cutoff point for his hope (and thus his anxiety) has simply been pushed back from 1:00 AM to 3:00 AM.
Here is what is actually happening in his mind:
1. The Moving Goalpost of Hope
• Earlier in his life / earlier in the evening: If she hadn't arrived by 1:00 AM (the limit set by the lift-boy), he would give up hope right then, and the anguish would hit him at 1:00 AM.
• Now: He has become so obsessed (and adept at self-deception) that he rationalizes waiting even longer. He keeps telling himself, "Maybe she's just late," extending his period of active waiting all the way until 3:00 AM.
2. What happens between 1:00 AM and 3:00 AM?
Between 1:00 and 3:00 AM, he is still clinging to the belief that she might still show up. Therefore, at 1:00 AM, he no longer feels the heartbreak he used to feel at 1:00 AM, because in his mind, the window of opportunity hasn't closed yet.
3. What happens after 3:00 AM?
After 3:00 AM, the realistic chance of her coming finally drops to absolute zero.
It’s not that he feels better by expecting her later; it's that his anxiety is tied directly to active anticipation.
• While hope is slowly dying (1:00 AM to 3:00 AM): He suffers the prolonged torture of watching the chances diminish minute by minute.
• Once 3:00 AM passes: Hope is completely dead. The agonizing uncertainty ends, replaced by numbness, exhaustion, or total resignation.

Why I stopped here?? Does every reader understand this or Proust put 2 sentences into one: (first) he still feels the pain after one, when the hope is in vain, for two hours, not as in the past that 1 is the cutting off point; (second), only after that, did he feel his hope is dead completely.

You stopped here for a very good reason: Proust is notoriously tricky, and Scott Moncrieff’s syntax made it a hurdle.
To answer your first question: No, definitely not every reader gets this on the first pass! You are wrestling with one of the most famously complex prose styles in world literature. Proust frequently compresses intense psychological shifts, paradoxes, and shifts in time into a single, winding sentence.
Did Proust pack two sentences into one?
Yes, absolutely. You dissected his mental logic brilliantly.
Proust compressed a two-stage psychological shift into one grammatical structure. If we unpack the two hidden ideas inside his single sentence, it looks exactly like what you identified:
1.        Sentence A (The Shift in the Deadline): In the past, 1:00 AM was my cutoff point where hope died and grief set in. Now, I stretch my hope all the way to 3:00 AM, so at 1:00 AM I no longer feel that sudden agony of defeat.
2.        Sentence B (The Prolonged Agony): Only when 3:00 AM finally arrives does the chance of her coming truly hit zero, ending the slow torture of watching hope diminish.
Why Proust wrote it as one sentence
Proust merged these two thoughts because, to him, time and psychology are continuous loops, not clean steps.
If he split it into two sentences, it would sound like a logical schedule: "First I wait until 1. Then I wait until 3."
By putting it in one sentence, he captures the fluidity of self-deception: the way the mind seamlessly glides past a deadline (1:00 AM) without even stopping to mourn, automatically recalibrating its own torture to a new hour (3:00 AM).
You stopping to puzzle over this means you're reading Proust the way he's meant to be read—slowly, dissecting the hidden mechanics of human denial!