I’ve lost a grandparent to COVID, albeit it was very sudden and very early-on. The one aspect I lost in this experience as opposed to previous grandparents was real closure. Nobody was able to visit him after the diagnosis, and he passed shortly after. The best closure I had was FaceTiming my parents, etc. about it. Apparently he’s currently in an urn in my aunt’s basement. It took a few weeks, but there was a moment when it hit me — the true sense that things really wouldn’t be the same, and wept for it.
Anyway, I wish you the best.