The reason is early game is pretty easy as the only thing that matters here are resistances. That's all you need to focus on.
What to pick up:
Jewels, Rings, Amulets, Rare items. Focus on resist on all of those items to have a rather easy time. Also don't forget to make a
Runeword Level: 15
+3 to Maximum Damage
+3% to Spell Damage
+(6 to 10)% to Summoned Minion Resistances
Elemental Resists +(16 to 20)%
(6 to 8)% Magic Find
+2 to Light Radius
for up to 20 all resists and using the armor that you get as a reward for the cain quest from akara for up to 15 all resists.
You can also pick up some Gems to fix the resistances that you didn't get from your gear if you want, which is mostly poison resist.
Aside from that you only need to pick up uniques.
Once you can go to mephisto, farm him for uniques in order to get arcane crystals, which allows you to create the unique items you need for your build. You can check uniques here: https://docs.median-xl.com/doc/items/tiereduniques
I'd advice making at least 1 weapon and 1 body armor unique, since you need the latter for the level challenge, and the first for damage output obviously, though I usually make everything unique aside from 1 slot for a potential honorific which you can get in act 5. It's important to fix your resistances, save stat points and other things like that. Btw you can get to level 43 just farming mephisto.
Once you are done with farming your gear up to Tier 2-3 (watch out for increased level requirement on uniques of a higher tier), go through normal difficulty, picking up only uniques, gems, rings, amulets and jewels.
The only jewels worth keeping are jewels that give -10% requirement at your stage of the game. Though I don't think they drop at that point yet. Later on you want to keep jewels with ilvl 99 for jewel crafting later on.
Just progress casually through normal and nightmare with those items. That's it. There's not much of a challenge here aside from Diablo and Baal on nightmare.