How long does it take for a gut to heal from acute onset Celiac?

I developed celiac disease about 4 years ago after my Covid vaccine shook it awake. I went through 3 or 4 months of hell, losing a ton of weight and ending up hospitalised in critical condition from dehydration and starvation - whereupon I was diagnosed with celiac disease. 4 years on, I'm much healthier, but I fear I'm still not absorbing nutrients properly. I've certainly put back on the weight I lost (not all of it, though), but I'm still deficient in Vit. D and it's starting to affect my brain a bit (brain fog, difficulty pushing through tasks, unsociable, etc.)

Given the state I was in 4 years ago, is it to be expected that my gut hasn't fully healed? According to a gastroenterologist, my childhood iron deficiency was a sign of Celiac long before it activated, so maybe there's more damage than I think.

What do you think??