Hey friend I'd love to help,
Your mana base has a great spread of fixing and utility. I would suggest that 34 number though, its definitely what I shoot for when I build my own decks.
Your ramp package looks decent, I would focus more on land ramp than artifact ramp though. You already have EvoSage in the deck, may as well play into his landfall ability. Three Visits, Skyshroud Claim, and Tempt with Discovery. Even if no one takes the Tempt deal, you still pay 4 mana to get Karn's Bastion and have a really difficult to interact with proliferate piece on the board.
Your card draw package is not bad either. A Skullclamp would be amazing on your Mites and infect/toxic creatures that might get targeted. Black Market Connections is strictly better than Phyrexian Arena, run it if you can. I also like Guardian Project better than Vanquishers Banner in this deck, its also an ETB which means if you blink Vishgraz you draw. It also costs less money, cheaper on mana, and hits on all of your creatures not just Phyrexians. Beast Whisperer is also a good card. Return of the Wildspeaker is a GOAT in this deck. You can buff for a big swing or draw a shit ton of cards off of your beefy commander's power. Your opponents having just 2 poison counters gets you 5 cards for 5 mana if RotW sees Vishgraz, that's an insane deal.
Your interaction package could stand some changes. Any opportunity you have to run Anguished Unmaking is one you should take. Anything that says destroy/exile a permanent is going to pull an immense amount of duty. Beast within and Generous gift are good cards because you can hit anything with them, including lands. Heroic intervention will save your ass from a bomb or keep someone off of targeting an important piece of yours. More blink effects not only give you a way to protect your commander from spot removal, they also come with 3 Mites. Eerie Interlude will blink your entire army saving you from sweepers.
As far as the overall strategy of the deck, I love your decisions. So many good choices here. I would swap out Trailblazer's Boots for Whispersilk Cloak. It affords Vishgraz some extra protection. A also don't care for this version of Ajani, but that's personal preference. Victimize is great reanimation tech, trading a mite for 2 of your best creatures in the grave is a no-brainer.
Here is a link of what changes I made from this post: https://www.moxfield.com/decks/mYRmlOuLNEmmQpisPXRi5w
It was a pleasure looking over this deck!