The weapons and armor are mostly linearly tiered and straightforward when comparing weapons between the same weapon class. This page covers weapons sorted by damage which generally corresponds to material tier. The order in the case of greatswords is as follows:
- Iron Greatsword (15 base damage)
- Steel Greatsword (17)
- Orcish Greatsword (18)
- Dwarven Greatsword (19)
- Elven, Nordic, Skyforge, Nord Hero Greatswords (20 damage, sorted by weight)
- Glass Greatsword (21)
- Ebony Greatsword (22)
- Stalhrim Greatsword (23)
- Daedric Greatsword (24)
- Dragonbone Greatsword (25)
(a weapon with an enchantment might be more powerful than a basic one of a lower tier)
While the progression is similar across types, other weapon types like one-handed swords and greataxes have different base stats such as range and attack speed that balance out their damage which might leave you with the impression that a big, low-tier two-handed hits as hard as a medium-tier one-handed. Couple that with weapon skills and the order stops being apparent across 1h/2h weapons.
Ultimately both for weapons and armor, you can just wear whatever has the biggest numbers as long as you can lift it. It's not something that should require a lot of thought put into it.