Zirda, the Dawnwaker is our companion. Zirda reduces cost of activated abilities, this way Omnispell Adept let us cast instants and sorceries (both at instant speed) for U and tap, a little reduction that helps us recovering missing Fires of Invention.

Fae of Wishes let us use our sideboard : for 3U+ U and Omnispell Adept we can cast a spell from sideboard if we have Zirda in play, 3U+2U without Zirda, bigger cost but still not impossible.

We use various mana ramp spells, there are varios so add which you see fit. I use Paradise Druid and Wolfwillow Haven because they are harder to destroy, Incubation Druid for various mana production and a defending body, Biomancer's Familiar is, like Zirda, an activated abilities cost reduction.

Fiend Artisan helps us tutoring Kenrith, the Returned King,Omnispell Adept or even Fae of Wishes.

Teferi, Time Raveler vs counterspells, some interactions that like Ashiok nightmare muse 's ult, bounce our/opp's stuff for whatever reason, 1 card draw isn't bad too.

Lands are important too : Ikoria's triomes are good, Eldraine's castles etc.

Sideboard is full on big spells, but you can obviosly use it as proper sb. For big spells try to use not x costed ones. If you wanna go deeper in memeland you can use untapping effects like High Alert.

If you don't like Teferi, Time Raveler, something logic, or Kenrith, the Returned King, why poor Ken???, you can embrace temur, meybe adding something that gives haste to our creatures and Ral, Storm Conduit, to copy our juicy spells. Talking about planeswalkers, Nissa, Who Shakes the World is an option, so [[Tamiyo, Collector of Tales.Lukka, Coppercoat Outcast and Vivien, Arkbow Ranger if you feel unlucky in the searching of the right creature.

Other copies of Zirda, the Dawnwaker can be added to main deck, but being it legendary, i don't think it's a good idea, meybe some resurrecting spells will be better.

Cycling version:

Companion
1 Zirda, the Dawnwaker (IKO) 233

Deck
4 Omnispell Adept (GRN) 49
3 Steam Vents (GRN) 257
4 Unpredictable Cyclone (IKO) 139
4 Fae of Wishes (ELD) 44
4 Shark Typhoon (IKO) 67
2 Ketria Triome (IKO) 250
4 Raugrin Triome (IKO) 251
2 Temple of Epiphany (M20) 253
3 Savai Triome (IKO) 253
3 Boon of the Wish-Giver (IKO) 43
4 Neutralize (IKO) 59
2 Yidaro, Wandering Monster (IKO) 141
1 Lotus Field (M20) 249
3 Sacred Foundry (GRN) 254
2 Kenrith, the Returned King (ELD) 303
1 Plains (IKO) 262
2 Ral, Storm Conduit (WAR) 211
1 Fabled Passage (ELD) 244
2 Inspired Ultimatum (IKO) 191
4 Deafening Clarion (GRN) 165
3 Hallowed Fountain (RNA) 251
1 Island (IKO) 265
1 Mountain (ANA) 59

Sideboard
1 Barrier Breach (IKO) 145
2 Mystical Dispute (ELD) 58
2 Wilt (IKO) 176
1 Flood of Tears (M20) 59
1 Zirda, the Dawnwaker (IKO) 233
1 Planewide Celebration (WAR) 172
1 Emergency Powers (RNA) 169
1 Eerie Ultimatum (IKO) 184
1 Inspired Ultimatum (IKO) 191
1 Genesis Ultimatum (IKO) 189
1 Ruinous Ultimatum (IKO) 204
1 Emergent Ultimatum (IKO) 185
1 Casualties of War (WAR) 187

Have fun!