Honjou Masayuki (Web Novel) vs Superman (Earth One): who would win?

Superman (Earth One) favored — Slight edge (~55%)

Honjou Masayuki (Web Novel) · Tensei Shitara Slime Datta Ken · Web Novel story

Tier
7-B
Attack Potency
City Level
Speed
Transonic
Durability
City Level

Superman (Earth One) · DC · Base

Tier
7-B
Attack Potency
City Level
Speed
Massively Hypersonic
Durability
City Level

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