This is the deck I played to master this month and from then onward to rank 14 with an overall score of 42:16. it combines the individual powerhouses of the currently best faction (primal) with the most efficient shadow card (Suffocate), Krull and the 3 good units Feln has to offer. Because of its focus around the heavy primal synergys the deck is comparable to the current Elysian build, but its a bit slower and lays heavier emphasis on turns 3-5 than turns 2-3 (but you still definitely want to play good things on turn 2 too). But like Ely you have to switch roles midgame quite often, which is one of the most important skills to learn for the modern midrange decks. The deck mostly has open matchups, meaning the right decisionmaking (and draw) is the deciding factor, with Hooru Kira being the worst matchup so far, but definitely still winnable (Sling is also hard to beat if they draw their Sling of the Chi
early, but a really good matchup if they dont).
Against aggressive decks (Skycrag Aggro/Yetis) you have efficient early interaction (Hurler, Suffocate, Permafrost, Maveloft) and early game units that survive Torch (Jennev, Fortune Teller). You will most likely always be the controlling player in that matchup (except for when you are at really low health and have to play more aggressive to win before they draw burn damage), so focus on controlling the board early and only take attacks when they are really save. Krull can sometimes be a nuisance in those matchups, but she can also give you the tempo you need (getting you Jarral torched and draw Krull the turn after, killing 2 uits with Maveloft for 3 mana with Know when to Hold Em). The market is not really build for classic aggro matchups because those matchups are good anyway and classic aggro is in a rough spot in general. The best pick depends on the situation: Champion is good when you just need a big unit that is hard to kill, Mirror image when you have a good blocker and want to double it. Swift Refusal can be good if you are at low health and expect burn spells.
Against the classical midrange decks that still are popular (Xenan, Shadowscar, Argenport) you are most often the beatdown (proactive player), but the role can sometimes switch, mostly depending on your draw (a lot of card draw and interaction means you are probably the controlling player instead). Your advantage in that matchup is that your cards are way more efficient, so your tempo is higher (especially true for your reactive cards: Answering a 4 or 5 mana unit with Maveloft, Permafrost or sometimes Suffocate is a huge tempo plus, because you can also lay down a threat/draw for more resources in the same turn). Vara can be a bit annoying because she negates the aegis on Chacu, which makes him way easier to answer, but Permafrost is still a good answer for her. Xenan Rampinator can also be problematic sometimes if they play it right and focus on ramping with Arcanum Hourglass
/Katra, The First Seal
instead of going all in on Grasping at Shadows
(this deck sometimes struggles with answering Katra, but has a lot of answers for Grasping between 4 Dazzle and 8 market access cards for Swift Refusal). Your market choice depends on the situation again: Chacu to play a proactive threat, Gustrider if you have Felrauks, Mirror Image to double a threat (Jarral or ChaCu) or Maveloft, Swift Refusal if you expect a board wipe or Grasping and Helio if you need a refill.
Against the more modern style of midrange (Kira, Elysian, TJP Soldiers) your reactive cards are less good because you dont get the same tempo plus out of Permafrosting a Jarral that you get from Permafrosting a Tasbu, the Forbidden
(Permafrost was a market card at the start because its bad against the 2 best decks, Elysian and Hooru Kira, but I saw a lot more big midrange decks, so I put it in the maindeck instead. This means that there is currently no removal in the market, which might be wrong). Your most efficient answers here are Maveloft (because she does kill something while surviving sometimes and she can be recycled with Krull) and Hurler (only for Hooru Kira, because they play a lot of X/1s. Hurler is especially efficient in terms of value if the Snowball kills something, because you dont go down a card in hand). In those matchups the roles switch constantly (but I think you are the controlling player slightly more often because your threats are less highrolly and you have more late game value), so try to learn when to be aggressive and when not (I dont think I can really write more about that, because roles depend on a ton of different factors and the best chance at learning those is to just play these matchups a lot and to learn from what worked and what didnt work). The reasoning behind what market card to grab mostly stays the same as it was against big midrange.
I wont write to much here for control matchups because hard control is almost completely dead right now. You are the beatdown in most games against control, so try to play proactive. Play around board wipes with negates if possible and grab ChaCu out of the market to have a good threat and Swift Refusal for board wipes.
Good luck and have fun!