Help me build my first Commander Deck!

Hey guys. I am returning to MTG after many years of not playing. I played a lot back in middle school with my best friend and his family but haven't played much since. I'm getting back into it with some of my friends and trying to build my first Commander deck (I used to just play standard). Right before I stopped playing was when Eldrazi first released and I had bought a standard red-black Eldrazi deck in a 2-deck starter pack and my best friend got the other deck in the pack. I always loved the Eldrazi creatures cause seeing the big numbers at the bottom made my caveman brain happy, so I'm building this colorless Eldrazi deck since I already had a few of the cards I needed and I like them a lot. Hoping to get get some advice on how to refine what I've got so far:

Deck List

My goal with this deck is to maximize the annihilate mileage. There are two main strategies I'm planning on utilizing, based on the commander that will be used.

Commander: [[Ulalek, the Fused Atrocity]]

Primary strategy: my idea is to use his ability to copy activated and triggered abilities to cast spells with the Eldrazi type after declaring attackers so that I can have the attacking creature's annihilate on the stack and copy them. I imagine that I will focus on getting out as many big Eldrazi with Annihilator 2+, attack with them all simultaneously, then cast my Eldrazi spell and pay Ulalek's 2 colorless to copy the spell and the Annihilate abilities on the stack, forcing people to wipe their boards. I have also included cards that have annihilate-adjacent abilities, like [[Ulamog, the Ceaseless Hunger]] and [[Bane of Bala Ged]]. I'm aware that this strategy is an easy way to become enemy #1 for the whole pod, thus my secondary strategy.

Commander: [[Azlask, the Swelling Scourge]]

Secondary strategy: with Azlask, the big Eldrazi with larger Annihilator numbers become a secondary bonus and not the main strategy. This strategy is meant to counter decks that can take my few big annihilators out of play, opting instead for death by a thousand cuts. It's really pretty straightforward, generate Spawns and Scions at a rate that is too high to completely shut down and activate Azlask's ability to give all of them Annihilate 1. Bonus points if I can get a few experience counters and beef them up enough to be an actual threat to player HP as well. Obviously with this strategy, I need to maximize the amount of cards I have that actually do generate Scions and Spawns.

As of now, this deck is pretty similar to the Ulalek pre-con, with a few notable changes in the fact that I've added all of the Eldrazi titans I own and whatever other Eldrazi cards I had already laying around. I mainly need help identifying what to take out so that I can add in the cards that enable these strategies. I have a small list of cards that either just don't contribute to a strategy revolving around annihilate:

[[Kozilek, the Great Distorion]], [[Emrakul, the Promised End]], [[Morophon the Boundless]], [[Essence Depleter]], [[Eldrazi Aggressor]], [[Culling Drone]], [[Blinding Drone]], [[Mind Stone]].

I'm hoping to double or triple the size of this list but getting stuck with analysis paralysis. I definitely focused way too heavily on creatures and artifacts. There are quite a few artifacts that help me out with mana-ramping (probably too many, like Mind Stone). The list of cards I'm currently looking at adding in are:

[[Ugin, the Ineffable]], [[Void Grafter]], [Dimensional Infiltrator]], [[Hope Ender-Coatl]], [[Elder Deep-Fiend]], [[Drownyard Behemoth]], [[Eldritch Immunity]], [[Kozilek's Command]], [[Not of this World]], [[Vedalken Orrery]], [[Winding Canyons]], [[Isochron Scepter]], [[Alchemist's Refuge]], [[Virtue of Knowledge]], [[Echoes of Eternity]], [[Kozilek's Unsealing]], [[Crib Swap]], [[Shields of Velis Vel]], [[Wings of Velis Vel]], [[Ego Erasure]], [[Maskwood Nexus]]

I'm happy to hear any suggestions on strategy, cards to take out, cards to add in or other general advice people have.