Separate holidays work for me. I had more than 50/50 custody for most of my kids' lives, and my home has always been the focus for "minor holidays" like Easter and Halloween and Thanksgiving and New Year's Eve. I still get more than 50/50 custody around the holidays. It's the arrangement all the single moms I've dated have chosen. In with the new, out with the old!
In your case, your Ds are adults, choose to live with XW, and the holidays have been focused around her family. Before making a grand pronouncement about all future holidays, I would consider trying whatever you plan to try for a season and see how it works out. Maybe it's great. Maybe it's terrible. Maybe your Ds understand or maybe they don't. After a year or two of space, you may love it, or be ready to reunite the holidays, or prefer to alternate houses for the holidays.
Just thoughts to take or leave. I wish you luck finding your way!
