We didn’t do the elf either, but sometimes (and she knew fine well it was me..) the teddies would have a tea party in her bedroom with her kitchen things, or be all sat around with biggest red reading a Christmas story to them.
Always had bedtime story in bed, but for December, had a short Christmas book (we had a French book about the adventures the Mouse family had for the 24 days before Christmas…I’d read that day in French and English, and sometimes we’d re-read previous days too, and then a chapter of the current chapter book).
On Christmas Eve, dinner was “platter” - basically lots of nice cold stuff out on the table (maybe some M&S party food heated), a mix of seasonal treats for DH and I, and things we knew DD would eat. She could try anything and decide she didn’t like it but there was plenty she did like.
After dinner on 24th, we opened the Christmas Eve box. Most of the year, it held the Christmas books and dvds stored away, but in 24th, it held her toddler Santa plastic plate and glass, family copy of Twas the night before Xmas, her sticking, new PJs for everyone, a lush lavendar robot bath bomb and a nice one for me, and a nice shower gel for DH. She laid out the cookies (which we bake in the afternoon - from scratch if we have time but from a frozen half batch of dough (from an earlier Dec baking) if not), and milk, lay out the stocking and go for relaxing bath into new PJs. Back downstairs for proper hot chocolate and then up to bed for TTNBC and a chapter…a calm journey to bed and hopefully sleep. We were using this, or a slightly more grown up version, until very late teens as DD found the routine very helpful.
We also had issues with candles for a 26 Dec birthday and that being the point of overwhelm …so we often didn’t light them and just cut the cake.
We stayed at home many years. We got into the habit that, when we went to DPs/DPILs, we rented a house locally to them to have a place we could retreat from the chaos of both houses (when we went “home” we had turkey lunch in 1 house and turkey dinner in the other as neither mother could be left out…but there were a lot of people in both). Our own place meant a calm start to the morning and Santa and our own presents, and breakfast we all liked. And we could go back there or for a walk between the 2 family houses, and leave the late one when we were done instead of having to deal with noise and chaos until late into the night and no sleep…
We also automatically built quiet time into every celebration day. And made sure we had snacks DD would eat in my bag, or on hand in whatever house we were in. And we kept a quiet spot at home, and tried to find one in all the other houses (or kept a coat ready for a walk in the rain if needed).