There are a lot of ways to pull this off
One of them:
you only need reasoning in hand
activate reasoning
activate metalfoes
activate aquamirror
summon aldhibah
activate meteonis
summon eltanin and summon aldhibah
summon fafnir
summon 2 idaten by detaching from fafnir and keep adding meteonis to hand
activate aquamirror
summon altais by tributing idaten
summon cross-sheep by using fafnir and altais
summon augus with aquamirror
activate both augus and sheep (augus chain link 2)
shuffle samsara and galaxy wave then draw them and discard metalfoes and aquamirror
activate samsara and galaxy wave
activate aquamirror
summon thuban by tributing augus
summon idaten -> add meteonis to hand
summon m7 -> add idaten to hand
summon idaten (from GY) by tributing m7 -> add absolute ritual to hand
summon idaten by shuffling megami -> add meteonis
summon m7 -> add idaten to hand
summon idaten (from GY) by tributing m7 -> add advanced ritual art to hand
summon idaten with advanced ritual art -> add meteonis to hand
summon m7 -> add idaten to hand
rinse and repeat
The deck list can be improved