OK. I have built a L70 Necro. By way of introduction, I played D, D2 and D3/LOD for about 10 years. Then my wife introduced me to WoW, which I've been playing for the last 5 years. However, I didn't enjoy anything about Shadowlands so came back to D3.
I'm looking for a couple of things:
One, I have always played solo but find at this level I need a playmate. So if anyone out there is interested, drop me a line (Spoiler: I am an old guy but I love the game); Two, I want to discuss ideas about the Necromancer build, I don't understand how some of the skills work. I currently have (1) Army of the Dead, (2) Bone Spear, (3) Corpse Lance, (4) Command Skeletons, (L) Grim Scythe and (R) Siphon blood. It's a powerful semi-melee/ranged attack. It's worked well but I'm into Greater Rifts now and while I can complete them I don't get thru fast enough for the big rewards. So I would like someone to suggest if and how I can improve the build to address this (and why this will work better -- that isn't a challenge, I just need to expand my education.

I am going the corpselance support build for Necromancer and the build has me taking Corpselance with Brittle and the pestilence set on top of that, if I were to take off the ability Corpselance and change it to another ability say for example Bone Spikes with Frost spikes, would the damage decrease an amount that it would not be worth it?

I decided to start making this build because i enjoyed the effect of Etched Sigil and Ranslor's Folly together. Legacy of Dreams is not required for this to work, you can also use Litany of the Undaunted and The Wailing Host, but LoD makes it a bit more flexible and doesn't require chancing perfect ring rolls. The greatest thing about this is that you don't need to worry about enemies being sprawled about or worry about pressing multiple spells. The damage does not really stack until you get more ancient legendaries equipped but once those start happening you will get to at least GR 80 with no trouble.
In terms of paragon stats, you should be maxing out movement speed and then just stacking into intelligence. You can put some stats into vitality if you are dying too often.
Try to stay away from diving into enemies too much and keep your distance. i found that the tornadoes do not spawn well with enemies up close.
Items:
Main hand: Deathwish
Off hand: Etched Sigil
Hands: Penders Purchase
Shoulders: Mantle of Channeling
Chest: Aquila Cuirass
Head: Andariel's Visage
Neck: Haunt of Vaxo
Wrists: Ancient Parthan Defenders
Belt: Cord of the Sherma
Legs: Skelon's Deceit (or Death's Bargain)
Feet: Irontoe Mudsputters
Ring 1: Convention of Elements
Ring 2: Stone of Jordan
Skills:
Energy TwisterWicked Wind
DisintegrateIntensify
Ice ArmorCrystallize
FamiliarSparkflint
Magic WeaponDeflection
Passives:
Blur
Unwavering Will
Temporal Flux
Power Hungry
Legendary Gems:
Esoteric Alteration
Legacy of Dreams
Bane of the Trapped
Kanai's Cube:
Valthek's Rebuke
The Twisted Sword
Oculus Ring
Ranslor's Folly
 
Feel free to comment with any changes you think would improve this or how it worked out for you.

Alright my first build... Here we go!
Now Necromancers aren't my 'main' classes but i play with them and im pretty good with them. And i come up with a build that is a bit boring, but ultra powerful, so lets begin!
1. Primary Attack, Primary attack should be bone spikes with the rune: Path of bones or Blood spikes. Why? Blood spikes are for people that lose health really quickly, and the blood spikes allow you to heal over the bleeding enemies you hit. Path of bones on the other hand is for people who have a lot of enemies in your way. Or you can have no rune, which i mildly recommend for people who are already strong just want to be a bit stronger :))
2. Secondary Attack. Should be Bone spear with the rune: Teeth or Blighted Marrow. Teeth is the one that i recommend for most people to use, why? Teeth fires more bone spears trough enemies, of course it deals not much damage but it damages more enemies. Plus, you can get an achievement for killing 40 enemies with bone spear within 3 seconds. Bligthed Marrow is for people that like to stay behind their minions and just fire their bone spear trough enemies. I call this build the lazy one. 
3. Corpses. Should be using Corpse Lance with the rune: Ricochet. Why? Ricochet allows you to have an chance to hit one more bonus enemy when you attack the first one. Which is pretty good.
4. Reanimation. Should be Command Skeletons with the rune: Kill Command,Frenzy and Dark Mending. Kill command is for people who are confident without their minions and want ther minions do yeet themself to enemies and kill them in one shot. Frenzy is the one that i recommend the most, this will allow you to command your skeletons to gain attack speed (which means more damage to the enemy) and it's just really that powerful. And Dark Mending is the last one. Dark mending is for people who lose health pretty quickly and want their minions to heal them.
5. Curses. Either Frailty or Leech. Frailty is for people who want their minions to deal much bigger damage with the rune: Scent of Blood. Why? Scent of blood will allow your minions to attack 15% increased damage, which is really helpful if you want your minions to do the job and not you. Leech is for people that lose a lot or a bit of health. With the rune Sanguine End. Cause it will allow you to heal 200% for the enemies that die.
6. Blood and Bone. This should be RIGHT OF THE BACK bone spirit with the rune: Poltergeist. Why? Bone spirit is powerful as heck and you should use it immediately when you get it. The rune Poltergeist will allow you to have 4 bone spirit, which means EVEN MORE DAMAGE THEN BEFORE HAHA.
7. Passive skills. I recommend: Overwhelming Essence for people that want more Essence and use a lot of Essence now and then. Spreading Malediction is for people that want their curses to deal a lot more damage, well not much but 1% increased damage is at least okay. Serration is also a really good passive skill, Serration is for people that like to stay behind while their minions do their business and you like to stay behind and just shoot bone spikes at them. And finally Aberrant Animator. For people that like to increase the thorns damage for their minions
And that's it! Took me a lot of time, and some repilies and thanks would be appreciated. And yeah, hope you are good with your necromancer now!
OH sorry if the text is black! I didn't realize that it would be hard to read on my post, cause when i m editing it looks white so... sorry :((

Hello! I have developed my own build for a monk but I can’t add it! How should I do it ?