Sparkles it is hard when your family have different expectations and desires for events than you do.
Sit down alone first, and think about what makes Christmas nice and meaningful for you? Is it the family gathering, or seeing friends and wider family, or going to church, or hearing festive music, or giving and receiving gifts, or having particular foods that are special for you, or the decorations, or the madness in the shops, or.......any of hundreds of other things that Christmas could mean to people?
Try to figure that part out first.
Then try to figure out (by thinking of what they have wanted to do in the past or by asking them) what makes Christmas special to your DH and DCs. (Will elder DC be home for Christmas or over the season, or not at all?)
Then see what you can do to take account of DH's views about "scaling back" but still keep the things that are meaningful to you and the family. So does DH not want to spend loads, but really wants turkey, or a particular seasonal special? Does younger DC have anything that they want to do?
Could DC set up a playlist for you all, including some music you love but also some things that they like? As a background to your day.
Do you want to change things now the DC are older? Would a party be a good idea? How could that work, when, who to invite, drinks and nibbles or a sit down meal? It can be quite cheap to do if you spend the time planning it well, in advance. And yes, hiring glasses can work well, some places will do boxes of (bottles of) wine for parties on "sale or return" basis so you can return anything not used etc.
How "scaled back" does DH want the decorations to be? Still have a tree? Accept a few things you do (that come out every year, not additional cost of new things), or just not do anything?
Would DH and DC like to play board games, or go for a walk, or do a Christmas Day Swim/Run/other mad event, as things change and the family celebration of Christmas evolves just as the family itself evolves and grows.
Would YOU like to go to a church service that you haven't been able to get to, or go out for a beer on Christmas morning with DH instead of worrying about the turkey?
Its as much about understanding each other's point of view and expectations of the season. And then finding a compromise between what you all would like and can afford to do (in terms of money, but also time and energy).