Fish in general. As a kid I absolutely disliked the strong taste and oily texture.
I'm very open with my foods and like to retry everything I disliked in the past, things I still don't like are Olives (weird metallic taste I don't like), Tomatoes (slimy texture at normal size, cherry tomats are fine), unaltered boiled egg yolks (so dry, so so dry), Oatmeal (texture issue), and a couple others I can't think of at the moment. I enjoy most of the texture based ones as soon as the texture is altered.
I definitely completed it solo. Finding spell books definitely helps, but just crafting spells with the given elements can be more than enough to muddle through.
You can give yourself armor to assist in your normal squishy wizard self that definitely helps with the tougher bits.