Zariman, get Phenmor, melt Archons. You really cant get wrong with Zariman weapons from Cavalero. They are easy to get, no RNG involved, you just play missions there, get materials, and rep, and boom you have solid end-game weapons. Alternatives for Zariman weapons are Kuva/Tennet weapons, or some rare Primes, or godroll Rivens. So Zariman weapons are easiest way to get one of the best weapons in the game.
Comparing to older content Zariman doesnt have that much grind at all. You just work towards unlocking stuff and thats all, really easy and simple. Almost no RNG involved apart from getting initial bank of Entrati Lantenrs, but eventually you will have them enough, just by doing missions.
Laetus - melts everything
Phenmor/Felarx - melts everything, and best Archon hunter
Praedos - my to go Acolyte farmer in SP with super easy and cheap heavy attack build
And best parts about Leatum and Phenmor - they are early in reputation, so like few days worth of reputation from 0 and you have both. Laetum is actually 0 rep requirements, Phenmor is 1st or 2nd rep level
Or you can always equip Hirudo on Inaros and cheese them that way. Inaros with Hirudo is "press one button and win pretty much every content while watching Netflix", except Arbitration, because pure melee not that good vs Arbitration drones xD You need some ranged weapon to kill Arbitration drones effectively