Short answer: Kronos: bigger cap, no tips, real banking attached.
EarnIn caps at $750/period and uses an "optional tip" model that drew a 2024 lawsuit. Kronos Pro caps at $1,000 with no mandatory tip, plus everything else (debit card, savings APY, crypto). Both are EWA so neither charges APR.
EarnIn's "Lightning Speed" charges $3.99 for instant funding; Kronos is instant on the in-app balance for free.