If you have browsed through my build suggestions, you may notice that most of my builds are hovering around level 70 and 80. These are not challenge builds that I intentionally keeping my character's level "low", rather I level up when needed and I find myself beating NG between level 70 and level 80 since my second build. (Remark: I level up freely on my first build so that I can afford to try out almost all the weapons and spells. Just part of learning process.)
These so-called level 120 limit for PvPers' are ideas carried on since Demon's Souls. In Demon's Souls and Dark Souls 1, players needed to have significant trade-off to maximize their character's ability even at level 120. However, in Dark Souls 3, as well as Bloodborne, level 70-80 would be more appropriate to beat NG, and players are required to have significant trade-off among various stats to maximize offensive and defensive abilities. At level 120, there will be no trade-off and easily overpowering in NG PvE.
Don't believe me? Try it out yourself using one of my PvE suggestions, especially, if you are willing to learn each PvE enemy's attack pattern and weakness. No summoning phantom is required.
This build is for role playing developing a melee character using solely Int stat and minimum str or dex, and this is not a range build shooting soul arrows the whole playthrough. This build also take advantage of stat enhancement rings, like Carthus Milkring, Knight's ring, Hunter's ring, and Scholar's ring, to avoid "unnecessary" stat leveling. This is not by any stretch of imagination a challenge build, it is simply a playthrough with better return on investment by leveling up stats more strategically.
Right Hand Weapon 1: Estoc (Raw infused Estoc allow buffing with Magic Weapon/Great Magic Weapon/Crystal Magic Weapon. Benefit is higher physical damage comparing to crystal or simple infusion, and magic buff result in better overall damage comparing to crystal or simple infusion.)
Right Hand Weapon 2: Light Crossbow/Short Bow/Composite Bow (Just for luring enemies out.)
Left Hand Weapon 1: Silver Eagle Kite Shield (If you use any of those two rapiers, learn to use shield splitter effectively)/Pontiff Knight Shield - Shield is optional, if you prefer dodging and rolling, then allocate that one stat point for strength to vigor.
Left Hand Weapon 2: Sorcerer's Staff/Heretic's Staff/Court Sorcerer's Staff (Progress in this order when available) or Pyromancy Flame
Armor: (light armor sets that keep <70% total weight ratio)
Crown of Dusk/Karla's Pointed Hat/Brass Helm
Undead Legion Armor/Brass Armor
Undead Legion Gauntlets/Brass Gauntlets
Undead Legion Leggings/Brass Leggings
Magic Weapon/Great Magic Weapon/Crystal Magic Weapon or Carthus Flame Arc (Fire weapon is useful against some bosses.)
Lingering Dragoncrest Ring/Knight's ring
Bellowing Dragoncrest Ring (useful for Farron Flashsword)/Magic Clutch Ring/Fire Clutch Ring/Hunter's ring
Stat leveling suggestion:
1. Level up endurance to 20 first.
2. Level up strength and dexterity for Estoc. (11 str, 12 dex)
3. Level up vitality and/or vigor a little bit, if needed.
4. Level up intelligence to 20 (I had these stats combination until Lothric Castle. +7 Raw Estoc buffed with Great Magic Weapon or Carthus Flame Arc has 355 damage and 355 damage respectively.)
5. Focus on leveling up intelligence to 40 or 45, if desired.
6. Level up attunement to 20 for more FP and additional slot for Farron Flashsword.
7. Level up vigor to 20 and you can easily finish first playthrough with ease.
You can choose starting class as deprived with vigor reduced from 21 to 20, for having club as starting weapon. Club can stunt enemies, even with starting 10 endurance. I have comfortably defeated the Uchigatana Swordsman next to Firelink Shrine without getting hurt, mind you, I didn't luring him to fall either.
As sorcerer, you will need to rely heavily on soul arrow or learn to use dagger effectively to get through early part of Highwall of Lothric. Infuse rapier to raw and equip it as soon as it becomes available. Alternatively, you can purchase long sword and infuse it with fire gem. Long sword's downward cut will be useful later when dealing with slugs at Cleansing Chapel or Farron Keep.
Recruit Yoel for the purpose of purchasing Magic Weapon. You also want to go through most, if not complete, Usurpation of Fire questline for the Morion Blade, which will be very useful at NG+.
I have strength at 11 for 100% physical absorption shield, otherwise, you can settle at lower strength and use Pontiff Knight Shield as alternative or forgo shield, if you are good at dodging and rolling.
Go through High Wall of Lothric, Undead Settlement, Road of Sacrifice, up to Clucifixion Woods the way you normally handle those areas. Don't forget recruiting Orbeck. Save titanite shards for your Estoc though, as Estoc won't be available until Greirat finish his first run. Estoc has one benefit over Rapier, which is Estoc's R2 attack. Estoc's R2 attack stunts enemies.
At Cleansing Chapel, you want to go as far as acquiring poisonbite ring, then you want to turn around and go through Farron Keep. There are two purposes to go through Farron Keep and reach Farron Keep Parameter. First, you want to defeat the giant crab in Farron Keep for the Lingering Dragoncrest Ring. Second, you want to get the Great Magic Weapon spell, which is accessible from Farron Keep Parameter bonfire.
Then, you can go back and clear Cleansing Chapel. You won't acquire Crystal Magic Weapon or Crystal Soul Spear until Grant Archive. Level up based on leveling suggestion or base on your comfortable level.
Regarding upgrading staves or pyromancy flame for this build, upgrading these items won't affect damage output of either the three levels of magic weapon nor Carthus Flame Arc, you can save titanite shards for upgrading other items, such as estoc or shield. You eventually should upgrade your Court Sorcerer's Staff and Pyromancy Flame for options to use other sorcerer or pyromancy spells at NG+, and upgraded sorcerer staff will be useful for Farron Flashsword. On the same argument, you can keep attunement at level 10 for most part of the playthrough as you won't be consuming too much FP by using just magic weapon and great magic weapon or Carthus flame arc. You will get more damage output by leveling up int stat early.
Key benefit of this build comparing to other melee builds is that you can afford to keep overall level low and attain relatively higher damage output using magic weapon buff spells.
If you like melee character, this is a fun alternative to traditional strength/dexterity/quality builds, especially you need to change pathing slightly to maximize your character's attack power as early as possible.
This build is assuming player possessing certain familiarity of the game, therefore, it may be a bit challenging on "blind" playthrough of Dark Souls 3.
Regarding relatively low strength and dexterity stats, since you will acquire rings, namely Knight's ring, Hunter's ring, and Scholar's ring late in the game, equipping those rings will offer slightly more weapon selection. Also, please keep in mind that two handing a weapon reduces strength requirement. Therefore, you can use heavier weapons when equipping Knight's ring. You don't need to level up strength or dexterity beyond 11 and 12 respectively for int scaling weapons, such as Crystal Sage's Rapier or Moonlight Greatsword or Greatsword of Judgement.