I doubt it is easy for senior royals. The late Queen Elizabeth II did hundreds of events per year into very old age.
Cocktail parties.
She probably reduced her time at these events in accordance to how she was feeling. Showing up as needed and going home when no longer needed.
I think the most difficult thing about being a Royal is the lack of freedom and the mandated pretense that you must exericse. You can’t have an honest opinion publicly. You must always exercise temperance, even when you are before intemperate crowds.
I don’t mean to imply that it’s easy, but it’s mostly appearance that you can’t vary from.