I said that I would find an Oath deck that works in the current meta and then write something about it. I think my 5-0 league and the second place finish by AdmiralSandman in a challenge with the same list is a good indicator that this variant is strong. In addition, very similar lists have now been doing well in challenges, so I will discuss the deck and some the cards in it as well as strategies. Here is a link to the list: https://www.mtggoldfish.com/deck/1944762#paper
This meta is full of Karn strategies and much fewer blue decks. The blue decks that are present in relevant numbers are PO and Xerox sporting Narset. Fish is also a competitor, but it is not as common. However, Fish is one the strongest decks against Oath. Survival is another deck to consider. With those decks in consideration I started tuning a deck using new cards for War of the Spark. The deck that I ended up with very much resembles decks that Brian Kelly had been successful with last year.
Eldrazi, Shops, Survival, Fish, and Xerox are decks that the Tinker-Sphinx of the Steel Wind package is good against, so I included it. I also realized how strong big mana decks were, so I used Wasteland and Damping Sphere to combat the mana base while also controlling the tempo of the game. I am not currently using Damping Sphere, but rather one Null Rod in its place and one in the sideboard. The other Oath creatures are Griselbrand and Gisela because Dredge is more prevalent than in the past. These creatures are the best package for aggressive, creature heavy decks. Arlin Kord also pairs nicely with them, and it is especially good in the Dredge matchup.
I'm currently using a fourth Mental Misstep to combat Xerox decks. The fourth Misstep replaced the Mindbreak trap. Xerox runs Swords to Plowshares and Pyroblasts, so the extra Misstep helps Oath protect its creatures and spells. The Xerox deck also uses Narset in a more powerful way than Oath and can protect it better, so adding more Narsets as a response has not been successful for me consistently.
Ashiok Dream Render is a very strong card against PO, Storm, Survival, and Dredge. I have even used it effectively against decks using Inventor's Fair.
The meta has basically been simplified because there are much fewer blue based decks to focus on. Those decks normally prey on Oath whenever possible, so this appears to be Oath's time to shine. I am looking forward to using Wren and Six to recur lands from the graveyard. I think it is going to be a good addition the deck.
I have noticed some things about different decks that are doing well in the challenge. Some people are cutting artifacts and still using Tinker. This is basically a gamble and can make it harder to play against Shops because of their mana taxing effects. Also, players are using Show and Tell. This card can be dangerous for the person casting it because of what the opponent can potentially put in play. So, those are my thoughts on the deck. I believe it is a great choice right now and I have really been enjoying it.