Hi guys, I'm a Legacy player who dabbles in Modern, but I've been enjoying this archetype, and I'd love to work on it a little. I like that it can play as a midrange deck with discard, removal, sweepers, etc, but then other games it goes turn 3 Karn, GG.
Here's my current list:

8 Swamp
4 Urza's Mine
4 Urza's Power Plant
4 Urza's Tower
3 Urborg, Tomb of Yawgmoth
1 Urza's Factory

4 Inquisition of Kozilek
4 Expedition Map
4 Talisman of Indulgence
2 Beseech The Queen
3 Read the Bones
3 Dismember
4 Solemn Simulacrum
2 Damnation
3 Diabolic Revelation
3 Wurmcoil Engine
1 Karn Liberated
1 Platinum Angel
1 Ugin, the Spirit Dragon
1 Sundering Titan

3 Nihil Spellbomb
2 Lost Legacy
2 Sadistic Sacrament
2 Thought-Knot Seer
2 Thoughtseize
1 Damnation
1 Crucible of Worlds
1 Night of Souls' Betrayal
1 Profane Command

I played in my local Modern event last week and ended up 3-1. I beat Mardu Tokens, Enter the Dragon (Enduring Ideal), and u/w Control. I lost to u/w Control. The list felt solid and I'm going to keep going with it. The only changes I'm currently considering are swapping one or both Thoughtseize for Duress or Blackmail. Burn is a matchup I don't mind having more 1 for 1 discard, but Thoughtseize can be painful. Nihil Spell bomb could easily be Relic, Surgical, or Leyline of the Void. I just had Spellbombs in a binder, while the other options are in other decks so I went with it. The Platinum angel could be something else, though I like the flying. Steel Hellkite, Rune Scarred Demon, or Grave Titan are the front runners.

Does anyone have any experience or recommendations for this deck/archetype? What do you think its bad match-ups are? I don't have enough games under my belt with it to know.