Sung Jin-Woo vs Kyoya Tachibana: who would win?

Sung Jin-Woo favored — Slight edge (~55%)

Sung Jin-Woo · Solo Leveling · True Shadow Monarch

Tier
LOW 6-B
Attack Potency
Small Country Level
Speed
Speed Of Light, up to Ftl
Durability
Small Country Level

Kyoya Tachibana · Tensei Shitara Slime Datta Ken · Base

Tier
LOW 6-B, up to 6-B
Attack Potency
Small Country Level, up to Country Level
Speed
Massively Hypersonic
Durability
Small Country Level, up to Country Level

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