Warden Eternal vs Sun: who would win?

Sun favored — Slight edge (~55%)

Warden Eternal · Halo · Mythic Variant

Tier
8-B
Attack Potency
Large Building Level, up to Town Level
Speed
Superhuman, up to Supersonic
Durability
City Block Level

Sun · Plants vs. Zombies · Sun Bomb

Tier
8-B
Attack Potency
City Block Level
Speed
Unknown
Durability
Unknown

A heuristic estimate from normalized VS Battles Wiki stats: tier, attack potency, speed and durability.