Yore-Tiller Nephilim + Medomai the Ageless + Phyrexian Altar

Decks

How it works

Declare Yore-Tiller Nephilim as an attacker.
Yore-Tiller Nephilim triggers, returning Medomai from your graveyard to the battlefield tapped and attacking.
Deal combat damage using Medomai, triggering its ability, causing you to take an extra turn after this one.
Activate Phyrexian Altar by sacrificing Medomai.
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.