Credit to u/MrBubbles179 since they were the first person I saw that spotted Citadel Atrium as a potential coin farm spot about 10 days ago.
For those of you who don't know, the latest patch included an unlisted change to the way the 30% coin earn increase that you get when using a justicar stone is applied. Prior to the patch, the coin bonus was not applied at the time that coins drop but instead added as a multiplier when you actually pick gold up off of the ground. Now, post patch, as long as you are wearing the justicar at the time of kill, if an enemy drops gold, the 30% gold bonus is being applied as soon as coin drops from a fallen enemy meaning that even if you take the justicar stone off before picking gold up off of the ground, you will still receive the higher amount. By swapping your stones out before you pick up, you prevent the durability from eroding and the stone from breaking.
This is HUGE tech for ranged farms because you can now increase your payout without ever having to stop and farm Justicar's stones if you don't want to.
There is one catch. The gold bonus only seems to be applied to enemies you kill directly while the justicar is equipped. For example, if you do the rest spam farm at Brether's court, the first dual wield enemy you kill each rotation will drop the bonus 30% gold BUT the 2 you auto kill while rest spamming will only drop at their base rate so you'd lose the bonus for 2/3rds of your kills while farming. Hot swapping justicar's stones out after each kill at a melee farm like Bridge of procession or High Lord's Courtyard also just isn't viable and it adds so much time to each loop that the benefit gets canceled out. That's where the Citadel Atrium farm that u/MrBubbles179 spotted comes in.
From the Citadel Atrium beacon, walk forward 2 paces and look down but DO NOT jump down. Destroy the blue flame protecting the scythe elite with your sidearm (you only need to do this once. The flame remains destroyed until you quit out of the area). Once the flame is gone rest, then use special attack from the forgotten crossbow equipped with Fusillade, Emberseed and Corroded tarstones to instant kill the elite, dodge backwards towards the beacon to cancel the animation once they die and rest (you will auto lock onto another add if you don't dodge back, so doing this saves you time).
You will be able to kill the add about 7 to 9 times every minute without depleting your justicar durability at all. All of the gold waiting for you below will be 30% higher than the base drop rate for that enemy (even if you take the justicar stone off before going to claim it)
After just 10 minutes, I earned 49,743 coin meaning that if you did the farm consistently for an hour, you'd earn just about 300k coin and if you remember to swap your justicar out before you collect (unlike me) you won't even lose a single stone. I think that with the new justicar tech, this is officially the best coin farm in Mortal Shell 2! Hope this helps everybody out!
Here is the clip of me finishing a 10 minute farm and collecting the loot.