The Tenth Doctor + Doom's Time Platform + Time Warp

Decks

How it works

You control a creature that can attack and that cannot be blocked or killed by an opponent.

Declare any creature as an attacker. When you do, Doom's Time Platform triggers, exiling Time Warp from your graveyard with two time counters on it.
Activate The Tenth Doctor by paying , removing the time counters from Time Warp.
Time Warp's suspend ability triggers, causing you to cast it without paying its mana cost.
Resolve Time Warp, causing you to take an extra turn after this one.
Repeat each turn.

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.