It really depends on the events of the day and your method, if you’re direct depositing to cash app and auto converting to sats, cash app wins as they’ll do that with absolutely no spread or fee. If you’re just smash buying sats, strike can have a better spread then cash app. During high volatility, strike’s spread can widen greater than cash app’s.
Generally speaking, direct deposit and auto convert on cash app is the cheapest way to attain sats i know of, but highly dependent on the price at the time of auto convet.
Strike’s automatic DCA has a relatively good spread and hedges volatility risk, so that’s what I use(daily or hourly).