I agree about the Lidl prosecco - it is lovely! I tend to buy the €7.99 bottles which are absolutely fine and lovely to drink, but the €11.99 bottles are seriously lush.
Often there will be offers if you buy 6 bottles together - money off, extra percentage back in your loyalty card etc, or specific offers on bottles/brands that have a promotion on..... - so if you can, I would try to put aside the money and actually buy it all together when you see an offer that suits you.
In our case, for Christmas, for 2 adults, we get 1 bottle of bubbles and 2 very nice bottles of white wine. We generally choose between opening bubbles or the white while dinner is cooking, and have wine with dinner too. But don't drink all 3 that day - across 8 hours we may finish 2 bottles. But it's nice to have a second bottle of the "dinner wine" in case we decide we don't want bubbles or we want an extra glass of it later (and then cork the bottle to finish another day).
Maybe think about having something for arrival - bubbles or mulled wine or a Buck's Fizz or something seasonally cocktail-ish. Some may want a beer instead.
I would allow roughly a half bottle per wine for dinner per person, but some may drink more than that. If you have an idea, as others says, about preferences towards red or white, that helps, but I would have roughly half and half otherwise. And maybe do that as 4-5 bottles of red, and 4-5 of white to cover dinner. If you are happy with 6 of each, that would work well, and you can always use the leftovers another time yourselves.
Have some soft drinks too, for drivers or other non-drinkers. And plenty of water as well for the table (we put out both sparkling and still water).