Been researching this exact question! Steel doors at
https://www.elegantentrydoors.ca/entry-steel-doors/ offer the best security and they're actually pretty affordable compared to solid wood. They won't warp, crack, or need repainting every few years like wood does. Energy efficiency is excellent too - most have foam cores that insulate better than traditional doors. The denting issue mentioned is real, but newer models have thicker gauge steel that's more resistant. We installed one last year and it's been perfect through all weather conditions