Gameplan:
The only attackers are Atraxa, Praetors' Voice, Grave Titan, and Storrev, Devkarin Lich. Storrev attacks to recover important dead cards from the graveyard. Between Atraxa. Tekuthal, and Kefnet, at least one should be kept as a flying blocker. Almost everything else is defense, control, counterspell, or card draw. The basic idea is to turtle and appear non-threatening, while mana ramping for game-ending big sorceries. Most of the planeswalkers have passive effects, or provide creature destruction/exile. They also distract players from my artifacts and provide tokens for defense. The deck has numerous cards to retrieve artifacts from the graveyard to keep the Aetherflux Reservoir + Bolas's Citadel combo from being broken. Most of the planeswalkers have card draw or Scry abilities, and in addition Soothsaying all assist with moving lands off of the library top or discarding good spells ONTO the library for Bolas's Citadel to keep working. Karn, the Great Creator: use his +1 to target opponent artifacts, destroy or exile them with other creature-targeting cards/abilities. Use his -2 to recover my own exiled artifacts. Ichormoon Gauntlet, Tekuthal, Inexorable Tide, Flux Channeler = high probability I'll be proliferating multiple times per turn.

Ramp (10)

Astral Cornucopia, Chromatic Lantern, Everflowing Chalice, Mana Vault, Pentad Prism, Sol Ring
Ashnod's Altar sac outlet for colorless
Sword of Feast and Famine untaps all lands
Tezzeret, Master of the Bridge makes creatures and planeswalkers cheaper
Tezzeret the Seeker and Teferi, Temporal Archmage can untap mana rocks

Card Draw & Card Advantage (17)

Mystic Remora, Rhystic Study, Ob Nixilis Reignited, Teferi, Time Raveler, Liliana, Dreadhorde General, Erebos, God of the Dead for card draw
Demonic Tutor, Vampiric Tutor, Liliana Vess, Tezzeret the Seeker for tutoring
Diabolic Vision, Narset Parter of Veils, Teferi, Temporal Archmage for scrying/draw
Aminatou, the Fateshifter, Brainstorm for card draw and also topdeck manipulation
Kasmina, Enigma Sage scrys and gives every PW the ability to move lands off the top of my library

Removal (9)

Cyclonic Rift, Urza's Ruinous Blast, Elspeth, Sun's Champion boardwipes
Ashiok, Nightmare Muse to bounce + exile
Kaya, Bane of the Dead and The Wanderer targeted creature exile
Ob Nixilis Reignited targeted creature destruction
Teferi, Time Raveler targeted artifact/creature/enchantment bounce
Liliana, Dreadhorde General player sacs two creatures, or ults to sac almost their whole board

Token Producers (7)

Anointed Procession amplifies every other producer
Ashiok, Nightmare Muse, Elspeth, Sun's Champion, Liliana, Dreadhorde General, Grave Titan, The Scarab God make blockers, mostly zombies

Finishers (9)

Aetherflux Reservoir: 50-life snipe
Bolas's Citadel: activated ability sac'ing tokens
Exsanguinate, Torment of Hailfire, Debt to the Deathless: all big X sorceries
Eerie Ultimatum after a boardwipe
Elspeth, Sun's Champion creature buff Emblem
Liliana Vess ults with full graveyards to steal a ton of creatures
Atraxa equipped with both Sword of Feast and Famine and Sword of Truth and Justice beats people in the face for commander damage. The proliferating +1/+1 counter quickly turns into lethal commander damage if she connects twice per player.

High-Priority Planned Changes:
Eternity Vessel, Tainted Sigil: lifegain artifacts, synergy with Bolas's Citadel, Aetherflux Reservoir, AND proliferation mechanic
The Chain Veil: even more planeswalker activations
Myojin of Cryptic Dreams: possibly a "win more" card due to high CMC and slow effectiveness. Use to copy Aetherflux Reservoir, Inexorable Tide, etc...
Empowered Autogenerator + Filigree Sages: mana ramp

Deck name comes from Flux Pavilion's song "Bass Cannon", and in this case refers to the combo of Bolas's Citadel and Aetherflux Reservoir.