Hullbreaker Horror + Emet-Selch, Unsundered // Hades, Sorcerer of Eld + Notorious Throng

Decks

How it works

You control a Rogue that does not have summoning sickness and that cannot be blocked by an opponent.
You have at least thirteen cards in your graveyard.

Deal combat damage to an opponent using a Rogue.
Cast Notorious Throng for its prowl cost by paying , causing you to take an extra turn after this one
Hullbreaker Horror triggers, returning Hades from the battlefield to your hand.
Resolve Notorious Throng, causing you to take an extra turn after this one.
Cast Emet-Selch by paying .
When Emet-Selch enters the battlefield, it triggers, causing you to loot.
At the beginning of your upkeep during your extra turn, Emet-Selch triggers, transforming itself into Hades.
Repeat.

In which brackets is this combo allowed, per Spellbook's Ruthless tier?

1–2 · Exhibition & Core

Spellbook classifies this as Ruthless — not for these brackets.

3 · Upgraded

Spellbook classifies this as Ruthless — not for these brackets.

4–5 · Optimized & cEDH

All combos are allowed.