the twinkling titanite down the broken stairs directly to the bonfire does not seem to respawn after using a bonfire ascetic. Is that a bug on my side or did this get patched? If this got PATCHED I would like to know if the souls aquired through killing the boss got changed too. Can anyone confirm this?

Kill lots of enemies

A good spot to farm is in the iron keep, go to the bonfire just before the Old Iron King and use a bonfire ascetic and there will be the iron Clad dark spirt at the bottom of the latter(if your at the bonfire room) the quickest method to kill him is to get him up the ladder and hit him off the edge (best weapon to use is the Ivory King greatsword, which I can do easily 3300 damage in total) and repeat till his dead, after that rest at the bonfire and go to the boss, wear anything to increase the souls and kill the boss, he'll give you about 200,000 souls on the 6th gameplay on the area, if you beat the boss 2 times you'll have 4 mil + the souls 2 mil and that should take 30 mins to do the fight 20 times if your fast and use poison... The next best spot is the Ivory King boss fight, use anything to increase the amount of souls and kill all the loyce until the second loyce closes the second gate then return to the bonfire and repeat the process. You'll earn ruffly 4000+ per kill and this is an unlimited source also if you collect the armour pieces you can sell them to Galvin for souls... They are my favourite ways to farm souls

Also, you can burn in Straid's Cell a lot of Ascetics Bonfire. The Undead Citizens will stay neutral until you attack them, one by one. In a Bonfire at Intensity 5, with Tseldora Set and Covetous Silver Serpent Ring +1, I receive 1163 souls for each Undead Citizen killed. Also, you can One Hit Kill them, since their HP is low than 250-255. For example: My Winged Spear+10 deals above 300 of Damage. Each Undead takes me 3-4 secs, so, in 20-25 seconds, you'll receive 5815 souls. This, in a Bonfire Lvl 5. It will scales more and more.

Guys... Just go to the iron keep. On bonfire intensity 2 with full soul absorption gear, i run about 60-80 thousand souls per run in the section from the first bonfire to the second bonfire. And the enemies are a joke with a greatshield/great hammer build.

Where can i find the soul vessel

The Rotten X 4

At least 800k/hr at the Grand Cathedral (before you kill the boss.) Have two Loyce knights fight off the Charred Loyce knights while you help. It helps to summon two NPC phantoms if you're overwhelmed. Right before the boss shows up banish your phantoms and use an Aged Feather and repeat. One run is less than 5minutes and will net you around 100k.

THE best soul farming spot is just before veldstat, if you can reliably kill the ghosts that spawn in a single shot (I use crystal soul spears) when they spawn with full soul absorb gear, you can get ~5k per kill on NG+7 (don't remember lesser playthroughs, but the ghosts are still worth more that most enemies. Because they spawn from a bell, you don't even need to move, they return in seconds and infinitely. I net roughly 15k every few seconds. The downside is you won't have the time to pick up the constantly increasing pile of items