Yeah, Newgrange is a great gig that usually turns out to be a damp squib.
Newgrange doesn't face directly East, but a bit South of that. Newgrange has a rising passage tomb, with a larger burial chamber at the top. On the various days around the Solstice, the rising sun shines increasingly up the passage. Then on the Solstice itself, the rising sun is low enough to shine completely up and illuminate the passage, illuminate the upper burial chamber, and confirm the exact solstice date. That's the theory, and the theory works.
The trouble is, it's always cloudy in the Ireland, and we're like a loo for the various passing weather formations. They all pass around us, but when a few clouds want to 'lift a leg' somewhere, those ones pass over Ireland and lift their legs here, while the rest politely look the other way

. So you only see sunshine on a winter solstice 00.01% of the time. In fact you never see a cloud free day here. Personally, I'm an hour's drive from Newgrange, but I never bothered getting up in the night, driving for an hour, and traipsing up only to freeze my backside & discover it was clouded over.
The winter solstice is actually confusing, because the next day, the sun goes down 2 or 3 minutes earlier, although it rises 5 minutes earlier. So the Romans, without such monumentally precise assistance, weren't sure about the solstice until the 25th or so. Hence the Great Roman Festival of "Natalis Sol Invictii"(= Saturnalia = "Birth of the Invincible Sun") wasn't celebrated until the 25th. So the stuff we associate with Christmas was going on long before (and during) the time Christ was alive. It simply was rebranded when Rome was paganising what little was left of "Christianity."
The Office of Public Works holds a 'lottery' where people are chosen to be up there on the interesting days. They probably pick carefully and junk the rest

.