Machu=Mach OTK

Putting aside geargia, now we shall look at the new number xyz in REDU:

Number 33: OOPArts Super Weapon - Machu=Mach

2 Level 5 monsters

Once per turn: You can detach 1 Xyz Material from this card to target 1 face-up monster your opponent controls; inflict damage to your opponent equal to the difference between its current ATK and original ATK, then this card gains ATK equal to the amount of damage inflicted.

This effect looks jank when reading, but combining with another jank card, it worked wonders althogether:

Minimum Guts

Tribute 1 monster you control to target 1 face-up monster your opponent controls; that target's ATK becomes 0 until the End Phase. This turn, when that target is destroyed by battle and sent to the Graveyard, inflict damage to your opponent equal to its original ATK.

In order to otk, you need a monster with at least 1900 ATK

1900(eff)+4300(atk)+1900(guts)=8100

Dianzhang also made a video on it, different approach by using:

By using Gagaga girl and magician to xyz, you can target 1 monster and make its attack becomes 0, so as long as your opponent's ATK is at least 2800 (which is abit hard lol), you can otk with it.

2800(eff)+5200(atk)=8000

In this meta, most of the monsters are at least that amount of atk (except dragonfly), so it's quite easy to achieve the otk. You can also target tragoedia or gorz token since ??? is 0 at base. Pure OOPArts would play this I guess... Also, I have thrown away all the cards that I thought of no use in GAOV sets... :( This teaches me to keep every single card.... III's death shall not be wasted!