Smaug vs Yixuan: who would win?

Yixuan favored — Slight edge (~55%)

Smaug · Lord of the Rings · Base

Tier

7-C, up to 7-A

Attack Potency

Town Level, up to Mountain Level

Speed

Superhuman, up to Subsonic

Durability

Town Level, up to Mountain Level

Yixuan · Zenless Zone Zero · Base

Tier

7-C, up to HIGH 7-C

Attack Potency

Town Level, up to Large Town Level

Speed

High Hypersonic, up to Massively Hypersonic

Durability

Town Level, up to Large Town Level

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