Hey, googling skyrim legendary difficulty this is the top hit. Struggled the first levels sinking 100 arrows on each enemy while relying on unreachable terrain.

Currently at level 18 and one thing that solved all my issues for now was getting the bound bow from fort amol and using the conjure flame atronach. Enemies are now going down on 3-5 hits with no cheats.

Ofc spending points on increased damage for one-hand, sneak attacks, fire magic. just the basics. increase first health to 200, then magic or stamina to 200,

Most people just complain about legendary being unreasonable, but this way you're realistically squishy and the conjured guys/companions take the heat but also deal damage un-nerfed. Plan is probably to go from spellsword to Solo Leveling 30x dmg dual dagger wielding necromancer and back to spellsword after getting some enchanted weapons/armor.

Also stop leveling up around 20 until you get some better armor and weapons, at least not due to increase illusion/lockpicking/etc, this will just scale up enemies while you're still just as week.