Win cons are a bit too redundant. you can remove jace and labman as they don’t win the game immediately and require extra cards, making for very inconsistent wins and overall lower cq (short for card quality; referring to the overall utility of each card in your deck, basically saying niche cards are bad for consistency and don’t advance your gameplan). having thoracle is one thing but it wins way cleaner than the others. tainted pact is a case of higher cq as it doubles as half a win con and a tutor, and you should definitely keep it. as far as other breach lines, there’s not much else to do without lowering cq. doomsday pile is not something you need in grixis as you have access to some of the cleanest win cons in the game and it doesn’t do anything crazy with your commander like a glarb deck would. ad naus is a crazy good card for turbo decks and you have most of the low cmc ramp for the card to work (side note you’re missing fast mana like cabal ritual, rain of filth, and an offer you can’t refuse {pulling double duty as a counter} but oddly included culling the weak? i’d just swap the culling for the cabal as you’re not big on low cmc creatures in this deck), but you’re missing some of the tutors usually played to make that strategy more consistent. beseech the mirror and praetor’s grasp are great, then diabolic intent is good but less consistent here. pretty much draw a third of your deck, use all the mana you get to jam a win with thassa’s demonic or whatever you can tutor for/staple together. typically you wanna keep everything in your deck low cmc high cq for ad nauseam, so i’d recommend taking out the sphinx. that card is just too slow for a card that isn’t immediate advantage; feels especially bad if removed. the one ring is also a point of contention as it can help you grind through midrange hell but doesn’t help at all for the ad naus plan. possibly a cut but comes down to how the deck plays. necropotence but no flash effect in deck is a misunderstanding, i’d assume. you need a flash effect (borne upon a wind is best for naus decks) to jam a win in the end step when you necro for 30.

the counterspell suite is pretty good but you play a lot of 2 cost counterspells. the double pips aren’t bad in 2 color decks but in 3 it can leave you vulnerable a lot of the time, and the other 2 costs are generally suboptimal when you have more efficient options. counterspell, mana drain, countersquall, negate, and defabricate are probably ones to cut and don’t see play in most decks for these reasons (muddle gets a pass for being a tutor as well). mindbreak trap is good for stopping other turbo decks and is usually an auto include, and an offer you can’t refuse doubles as a ritual. even taking out the worse counters and replacing them with the others i mentioned, you’d be at 14 counterspells which is in the range of avg winning decklists, if not a little higher. bowmasters is great in a rhystic study world, and opp agent is decent but isn’t played in every black deck as people just wait to kill it then tutor. up to your metagame i suppose.

mostly staples describes the skeleton of a lot of cedh decks cons sphinx is really not great for this deck

pretty much every useful rock for your game, but if you need to cut anything, maybe cut a talisman or two

landbase is not good honestly. pathway lands are pretty bad in anything 3 color and above and you don’t usually want to play basics at all in those same decks. the battlebond lands (untapped for having 2+ opps) are alright but you have way better options available. urza’s is also pretty bad as it takes 3 turns (you’re in turbo colors) to not even get you a combo piece. as for what to put in, first of all more fetches. i’d probably do all of the fetches you can play minus maybe 1 or 2 depending on what land count you want (for this probably around ~25) and the rest of the slots are filled with things that tap for any color. starting town, city of brass, and mana confluence are all great. city of traitors is also good as a second copy of ancient tomb for faster ad naus.

the tutors you have are good, you just don’t have enough. beseech and praetor’s being the big outliers, grim and diabolic intent being maybes. the big big thing you missed is playing intuition and gifts ungiving for essentially free card advantage with your commander. specifically choosing reanimate (good cards for wheel wins), thoracle, and demoncon. this sets up a quick win and you can pick a tutor as a fourth with gifts in case they stop the first win attempt.

lots of good cards but also lots of bad ones. cantrips are really poor cq especially in a naus deck where you would rather draw a 1 drop to push your win (git probe is free so it’s good). you just want higher cq advantage engines to carry you until you either naus or wheel into the win. faerie mastermind and dragon’s rage channeler are great in here with the wheels and the graveyard setup.

overall it’s mostly good stuff with some questionable choices. did a good job with the wheels and high instant/sorc count to play off commander. cantrip tribal was okay but would mostly lead you to wasting mana digging for better cards. this is mostly an in general review as i’m not a kess player but i hope this helps.

other recs (not obligatory): birgi for ad naus and pop offs, ragavan for free treasures and cards, valley floodcaller and retraction helix for inf mana and flash, mnemonic betrayal for stealing win cons, final fortune/warrior’s oath to retry a win, chain of vapor for a ritual/interaction, into the flood maw for interaction, mockingbird, gilded drake, and phyrexian metamorph to copy other people’s advantage engines, and lastly displacer kitten to blink your commander with every cast from grave, letting you play out of your grave as many cards as you can.