@allysseriordan The first time this happened to me, it was excruciating.
I dropped all the way back to picture books and gradually worked my way up through children's books and young adult to fantasy, Georgette Heyer, and cozy mysteries. With setbacks, I eventually regained hard science fiction and even Dorothy Sayers mysteries.
New material is still something I approach with caution (the better rhe writing, the more effort it takes), and I still can't do sustained technical reading (technical papers require careful titration).
But after six years with long covid, just this week I reached a new milestone: I've been able to handle multiple novels at once - one familiar novel in progress at bedtime, and another in progress being read with breakfast and lunch.
Progress is slow and unpredictable, but it happens!