Esika's Chariot + There and Back Again + Hellkite Charger

Exhibition

Decks

How it works

At the beginning of your precombat main phase, There and Back Again triggers, putting a lore counter on it.
There and Back Again's third chapter ability triggers, creating a legendary 6/6 Smaug creature token and causing you to sacrifice There and Back Again.
Activate Esika's Chariot's crew ability by tapping the Smaug token, causing Esika's Chariot to become an artifact creature until end of turn.
Declare Esika's Chariot and Hellkite Charger as attackers, triggering their abilities.
Resolve the Esika's Chariot's trigger, creating a copy of the Smaug token.
Put either Smaug token into your graveyard due to the legend rule.
When the Smaug token dies, it triggers, creating fourteen Treasure tokens.
Activate seven Treasures by tapping and sacrificing them, adding .
Resolve the Hellkite Charger trigger, causing you to pay to untap all attacking creatures and to get an additional combat phase after this one.
Repeat from step 4 each combat phase.

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

1–2 · Exhibition & Core

Allowed in this bracket.

3 · Upgraded

Allowed in this bracket.

4–5 · Optimized & cEDH

All combos are allowed.