Best DPR using the Horizon Walker's teleporting feature?

Question

I am hoping to play a 15th level character in my new campaign. We are starting from that level and progressing from there.
What is the best combination of my levels, ASI, feats, magic items, etc, with the optimization objective being to maximize Damage Per Round(DPR). Multiclassing and all variant rules are permitted as long as they are RAW. I would like this character to do the most DPR at level 20, even if the earlier levels are not as optimized because of this. Please allow for the use of the feature of the horizon walkers 11th level feature - do not make a build which cannot use it.

Use point buy or standard array for ability score generating

Assume

1. Any amount of enemies 2)Assume AC 18 and saving throws of +8 3)Assume no vulnerabilities/resistances or immunities (but a better build will be one with less resisted/immune damage types) 4)The rest of the party are a redemption paladin 15/a sorcerer (divine soul) 5, hexblade 10/fighter 1, hexblade 14/grave cleric 15/wizard 15. Only one character will buff me at a time, and the hexblades are both using concentration.
2. Whichever will give me more DPR - multiple enemies or single target - use in your calculations

Restrictions

The Character requires at least eleven levels in Ranger(Horizon Walker) to use its teleporting ability.

Books

1. All official WotC books allowed
2. Anything RAW allowed
3. All magic items available - but only one artifact, and two legendary items (except moonblade because of its unlimited damage)
4. No wish/wish-granting
5. Aim for consistency - things that can only be used once per short/long rest aren't included, but if it can be used if it is available for 4 encounters, with one short rest in the middle.

Answer 1

HW11/Champ4 = reliable 120 DPR

Since no one gave this a shot, I thought I'd write something.

Horizon Walker 11 / Champion 4

Horizon Walker:

• Fighting Style: Two-Weapon Fighting
• ASI
• Extra Attack
• ASI
• Distant Strike
• Hunter's Mark

Champion:

• Action Surge
• Improved Critical
• ASI

Equipment:

• 2x Rakdos Riteknife (+1 knife +5d4, I assume you go kill 10 rats before the game starts)*
• Hand of Vecna (+2d8 on attacks with one hand)
• A backpack filled with Potions of Speed (for +1 attack per turn)
• 2x Manual of Quickness of Action (to get 20 dex)

*Note: Vorpal sword would deal more, but only if the DM lets you instagib, otherwise Riteknives are better even with Elven Accuracy (5d4 = 12.5 on average, vs 14.25% chance for 6d8 = 14.25% * 27 = 3.8). You also need to spend a feat to dual wield them.

Each turn

Attack with extra attack + attack from Distant Strike + attack from Potion of Speed + Two-Weapon Fighting offhand attack = 5 attacks per turn

Each attack is 1d4 (dagger) + 1 (magic) + 5 (dex) + 5d4 (Rakdos Riteknife) + 1d6 (hunter's mark) = 24.5 Each main hand attack deals a bonus 9 (Hand of Vecna) + 24.5 = 33.5

Hit bonus is 5 (prof) + 5 (dex) + 1 (weapon) = 11

Hit chance vs 18 AC = 1 - (AC - Hit Bonus - 1)/20 = 1 - (18 - 11 - 1) / 20 = 70% 1 round is 4 main hand attacks (33.5 * 4) plus 1 offhand attack (24.5) with 70% chance to hit each = ((33.5 * 4) + 24.5) * 70% = 111

Don't forget we also have 19-20 crit range (champion), so that's a bonus 1d4 (dagger) + 5d4 (Rakdos Riteknife) + 1d6 (hunter's mark) = 18.5 damage every 2 in 20 attacks, so on average + 1.85 damage per attack. Adding that to our 111 we get 111 + 1.85 * 5 = 120.25 DPR on average.

You'll notice I didn't spend any of those 3 ASIs or use Action Surge, and only used 3 items plus some consumables. Personally I think you should keep in mind that DPR isn't everything, you can only deal the damage that you are in the position to deal. Consider spending those ASIs and items to increase your utility.