Adding more Karn and putting 1 copy of either of the Liquidmetal in the sidedeck would help get your combo assmbeled easier. If you are playing this deck with the idea of casual (bo1) I would advise a side deck of 7 cards for Karn to search for artifacts (default 15 for bo3). The artifacts can be something like Tormod's Crypt or similar situationally useful cards. You could also include a late game payoff to the sidedeck as well to help end the game.

Would suggest adding some kind of ramp like a 1 dorp mana producer so you can assmble your combo faster. The mana production can be either creatures like Llanowar Elves or auras for your lands like Wild Growth or if you add more "forest" subtyping to your lands then Utopia Sprawl would also work to help fix mana. To add forest dual type lands you could try to get some "shock" lands like Stomping Ground to replace the deserts, but the more budget friendly Wooded Ridgeline would aslo work. These lands would also help with your reveal lands as you could reveal these tap lands to help your land enter untapped in a pinch. Could also use the ramp spell Farseek as an option if you choose to add those to your mana base as they can be searched for with this spell and put to board.

I think your mana curve is also a bit greedy with only 18 lands while having multpile cards over 4 mana in your deck. With this mana curve you may want to be sitting around 20 lands for a more consistant draw to play your spells. Afterall the Inferno Titan is slow to the board and likely a win more card if you have your combo shutting down your opponents ability to be on board. If you want to keep land count low, then you could try adding cards like Generous Ent as your late game pay off in place of the Titan as you could cycle it to find a land and if you added the dual type lands then you could search for those if the share the land type (Radiant Grove / Temple Garden or Wooded Ridgeline / Stomping Ground). The Ent could even be brought back from the grave late game if you put something like Portal to Phyrexia in your side deck for Karn to find when you are not needing him to do something else at the time.

Fun card option if you are more on the sacrifice 1 drop creature binge, you could use the enchatment Abiding Grace to keep bringing back 1 drops or gaining life ewhen there is nothing to bring back. Not really recomended, but something I thought fit your deck idea.

Hope these help your deck idea.