I know a person who played this and I dont remember what his commander was but it was GBW and he ran contamination. Most obnoxious thing he ever did. But for your deck you certainly look like you know what your doing as you have a minimum of 1.5k to build this deck and defintely see it being really competitive in comparison. Have you thought about maybe running azusa or possibly finale of devastation ?

Deathholme Finale of Devastation is already in the deck, and i don't have enough lands in the deck, and don't worry about landfall that much to warrant Azusa, Lost but Seeking

What do you mean with "Selvala damage either straight out 2 damage a turn or with Umbral Mantle"?

Yisan, the Wanderer Bard isn't in the list, but in your "Card Choices" section. I suppose that's because Staff of Domination and Aetherflux Reservoir are your win-conditions? I think I'd still rather play Yisan instead of Finale of Devastation .

I'd put Aura of Silence in the maybeboard at least. It stops a lot of artifact based combos and slows opponents doen by a lot, if you can get it out early.

Sephyrias what it means is actually damaging people with selvala 2 damage each turn, or making selvala swing for lethal with Umbral Mantle due to her getting up to 22 commander damage. Yes, Yisan, the Wanderer Bard is no longer in my list, i have an average cmc of 2.7 so figured it wasn't worth it anymore so had it removed, still have to update the primer, Finale of Devastation is 1 of 3 ways i can touch my graveyard so it is definitely a must. I used to have a lot of stax in the deck, but through playing experience found it made the deck too slow/clunky. So i made it faster.