This is definitely a good start. You're building extra turn Narset, we just need to fix up a few things. Namely, the gameplan, and then the win condition.
Your top priority with Narset is casting her as soon as possible. Because you have a bunch of extra turn/extra combat spells, you could very well win the game by having Narset attack once. So you need to cast her fast, and preferably give her haste (she has hexproof, so she can easily survive a turn cycle). For mana ramp, keep all of the stuff that is 2 mana or less. You'll also want to try to get
Jeweled Amulet,
Mind Stone, and
Generator Servant. Although they might break your budget, try to also include
Mana Vault and
Chrome Mox. For haste enablers,
Need for Speed is amazing (you don't need lands once Narset is out), and
Torch Courier is the creature-based equivalent.
Lightning Greaves is a better option than
Expedite. Also, did I mention
Generator Servant? It's worth mentioning twice.
For win-condition, I don't think you should go with your current strategy with
Aetherflux Reservoir. Because both lines require at least one creature (
Dualcaster Mage or
Naru Meha, Master Wizard) and one of the combo cards
in hand. The risk of Narset exiling both of those creatures are too high. Instead, an easier combo involves
Approach of the Second Sun,
Nexus of Fate, and
Beacon of Tomorrows. Because you have so many extra combat/extra turn spells, and many ways of copying them, you will eventually dig into your whole deck.
Beacon of Tomorrows,
Nexus of Fate, and
Approach of the Second Sun will keep shuffling back into your library, so you don't need to worry about decking yourself. Instead, you will eventually draw
Approach of the Second Sun (it is very likely that Approach, Nexus, and Beacon will be the last three cards in your deck) and then you can hard-cast it to win the game. This method is already budget, but if you really wanted to improve it, you can include
Enter the Infinite (you already have the
Omniscience to go with it).
Now your probably wondering what cards you should take out. But instead of me telling you which ones it should be, I want to hear what you think you should remove. This will help with decision making in the future, especially if you plan on making more cEDH decks in the future. If you need advice, check out this thread.
https://deckstats.net/forum/index.php/topic,42562