Flash (Barry Allen) (Post-Crisis) vs Sunday: who would win?

Sunday favored — Slight edge (~55%)

Flash (Barry Allen) (Post-Crisis) · DC · Base

Tier

2-A, up to HIGH 1-A

Attack Potency

Multiverse Level+, up to High Outerverse Level

Speed

Massively Ftl+, up to Immeasurable

Durability

Multiverse Level+, up to High Outerverse Level

Sunday · Honkai: Star Rail · False God Sunday

Tier

2-A

Attack Potency

Multiverse Level+

Speed

Infinite

Durability

Multiverse Level+

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