Solarmon vs Kei Uzuki: who would win?

Solarmon favored — Slight edge (~55%)

Solarmon · Digimon · Base

Tier
HIGH 8-C
Attack Potency
Large Building Level
Speed
Massively Hypersonic+
Durability
Large Building Level

Kei Uzuki · Sakamoto Days · Current

Tier
HIGH 8-C
Attack Potency
Large Building Level
Speed
Hypersonic+
Durability
Large Building Level

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