Medomai the Ageless + Idris, Soul of the TARDIS + Sword of Truth and Justice + Encroaching Mycosynth

How it works

Deal combat damage to an opponent using Medomai the Ageless.
Medomai the Ageless triggers, causing you to take an extra turn after this one.
Cast Idris by paying .
When Idris enters the battlefield, it triggers, exiling Medomai the Ageless until Idris leaves the battlefield.
Activate Sword of Truth and Justice's equip ability by paying , attaching it to Idris.
Move to your extra turn.
At the beginning of your upkeep, Idris's vanishing ability triggers, removing a time counter from it.
Deal combat damage to an opponent using Idris.
Idris and Sword of Truth and Justice trigger.
Resolve the Idris trigger, causing you to take an extra turn after this one.
Resolve the Sword of Truth and Justice trigger, putting a +1/+1 counter on a creature you control, then putting a time counter on Idris.
Repeat from step 6.

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.