TBH I've almost totally gone off the big reds. I'll still drink them over winter especially in Canberra, but otherwise I mostly pour the big Barossa reds I have left in the cellar for guests. My go to for Xmas has generally been a Clonakilla S/V or Syrah, although last year I did a Nerello Mascalase from Etna cos we did the outdoor charcuterie lunch.
Old fashioned wine is fine and some even still makes it into my buying roster - Wynn's cabernet for eg. And I love grabbing something like a Teusner or a Torbreck or a Kalleske or whatever and showing people hey, you love that f**ken Pepperjack or whatever but this is what you could actually be drinking. But also we went to Chateau Tanunda when we were in the Barossa and I literally think I found everything near to undrinkable.
It's not even that SA wines are the problem, it's just the stagnation of it. I love a lot of Barossa and McClaren wineries. Langmeil like you said, always great wines but I think it's because they have moved with the times a bit - even their big Barossa shiraz have a point of difference. I always find a cherry cola note in the Valley Floor shiraz and they usually avoid making it syrupy. St Hallett, Kalleske, Teusner, Torbreck, Two Hands, and loads of others make great wine.
But the SA wineries I love are like Yelland & Papps and SC Pannell, who are doing super cool stuff. Which is a great sign! There is movement, and towards alternate varieties, it's just been a bit slow. The Y & P Vin de Soif is beautiful and almost the total opposite of what Barossa red "should be", and the SCP range has more alternate wines than standards.
That Aldi Nero is amazing value and I grab a bunch every time they have it here. Even when I'm spending a bit more, like, you can get this and plenty of other weird wines for $20 at Dans (although it's not on their website which is weird cos I got like a month ago)
https://www.billybuttonwines.com.au/product/2021-billy-button-rosso