If one of those modes is chosen with either the third or fourth mode and the only target is an illegal target when the ability would resolve, the ability does not resolve and the other chosen mode has no effect
For example in this deck, the removal potential is much greater than the measured one, as every instant damage dealer archer can be equipped with a deathtouch enabler and works as a repeatable removal tool combined with Ohabi (mostly target, but few mass removal as well)
You build decks with Lurrus in mind whether you play it or not
Lifegain also overlaps heavily with two other archetypes worth raiding for pieces: vampire aristocrats (Vito, Epicure, Licia all live here) and go-wide tokens (every token that enters is a Soul Warden trigger)
Green Sun's Zenith has two problems: it makes green-based creature decks much more consistent with its toolbox play pattern and offers a Turn 1 Rampant Growth with the assistance of Dryad Arbor
Its a rock-solid precon, but its very linear, and outside the use of role tokens on three new cards, it does little to differentiate itself from enchantment-based precons of the past