Idk man, I lived and worked through all the changes to react and had a good amount of experience with state based programming before that. I definitely know several people who would laugh at the complexity of hooks and the react life-cycle. There’s some gotchas but nothing that’s out of this world.
So yeah I think it’s possible for a highly experienced developer to have React mostly down in two days. I just straight up disagree based on my experience. I suggested 5-6 for a reasonable average for someone with 5+ years of good experience in that general domain. My apprentice was mostly a python Dev too and he was better than my colleage of three years after a few days.