RoboSats is "minimized custody" but not "fully custodyless".
At any given time, robosats node most likely holds no funds of any user. It is for ~1sec that it charges the seller's escrow and sends the Sats to the buyer. Making this step atomic is a priority, yet unclear whether if possible at all: so it needs to be a mutually trusted node who does it atm.
Okay, so custodial (at least by my definition) because they can steal/lose funds during the transaction.