Honestly, these threads are a load of rubbish tbh.
You get:
-
posts from heavily pregnant women wanting reassurance that it's not too bad. Dozens of responses about how newborns are fine, it was their favourite bit etc and not to worry
-
posts from new mums dating how hard it is. You get signed off responses about how is the hardest stage and it gets better after a couple of months, and how lots of babies sleep through by 3-6 months or just wake up once or twice
-
sleep posts from mums 6-12 months in wondering why their babies don't sleep when they were told that it would get better (see point 2 above). They then get told that it's rare for babies to sleep well early on, their expectations are too optimistic (although entirely in keeping with what they were told) and that posters children didn't sleep through for 5 years etc.
Generally most posters will try to be reassuring to the person irrespective of the truth of the matter. Not to say people are lying, but that but everyone will choose to reply on a particular thread, especially if it doesn't fit in with providing the reassurance the OP is looking for.
Telling a heavily pregnant woman that yes, newborn staff might be hell (it wasn't for me btw, i just know it is for some) isn't going to make her feel better, so people don't say that, and you end up with disproportionately positive stories.
Saying to a woman with a newborn who is struggling that no, it actually got a lot harder and if might be years until they get a decent sleep isn't going to make them feel better, so you get disproportionately posts saying that it's a very short term thing.
For me, i give my (non sleeping for I've if them) newborns very rest, toddlers hard, and no they still don't sleep. But I know others that found newborns hard but they're babies then slept.
I'm not sure you can know how you'll find it until you are in it, and possibly not until you are through it and looking back.
But good or bad, everything is a phase, and the only guarantee is that it changes over time.