So this is the strat that I'm looking at, at the moment.
Get into game with Darkness Starter, sell the most expensive cards to buy 5x Spark, 5x Dagger, 6x Photon.
Go into Arena to farm up to 500 Score, and in the process you'll get enough gold through EMs. I considered farming 1hp Plat decks to get a super fast Electrum with the upgraded rare from the special spin, but Plat offers no Score upon win.
Buy 24 water pillars, 6 wings, 6 NT, 2 Purify (the lattermost can be taken out to optimise the run a bit more, maybe).
Beat AI0, 1, 2, using standard NT rush of 24 pillar 6NT.
Switch deck to Wings w/ NT, and accept all the quests
Reroll False God until you find Serket, and win with Wings NT
I did this on low quality and fast AI, it speeds it up quite a bit. Didn't record time, as I was just exploring possibilities
I chose NT as it is a fast deck, and overlaps by being able to kill one of the FGs. Buying the deck costs 858, so you'll need to farm a bit so you have enough to reroll AI
Spoiler for Decks for easy copypaste:
Arena Farmer
Hover over cards for details, click for permalink
4sa 4sa 4sa 4t3 4t3 4t3 4t3 4t3 4t3 5l9 5l9 5l9 5l9 5l9 5l9 5uk 5uk 5uk 5uk 5uk 5uk 5uk 5uk 5uk 61p 61p 61p 61p 61p 61p 8pp
Quest Clear
Hover over cards for details, click for permalink
5i4 5i4 5i4 5i4 5i4 5i4 5i4 5i4 5i4 5i4 5i4 5i4 5i4 5i4 5i4 5i4 5i4 5i4 5i4 5i4 5i4 5i4 5i4 5i4 5ig 5ig 5ig 5ig 5ig 5ig 8pp
Serket
Hover over cards for details, click for permalink
5i4 5i4 5i4 5i4 5i4 5i4 5i4 5i4 5i4 5i4 5i4 5i4 5i4 5i4 5i4 5i4 5ia 5ia 5ig 5ig 5ig 5ig 5ig 5ig 5oo 5oo 5oo 5oo 5oo 5oo 8pr
Also SummoningSalt is great