It is almost impossible to find a higher powered out-runner designed for 5S; manufacturers have discovered that with new FET technology it is cheaper & easier to make low Kv, high voltage motors. Just a few years ago, it was rare to find medium to large motors for 12S batteries, now they are everywhere and motors above 1.5Kw designed for 6S and lower are becoming scarce.

For a high powered motor on 5S, you will probably have to turn to in-runners like this: https://hobbyking.com/en_us/dt38-620...ner-motor.html. The smaller diameter means they have less torque than a similar power out-runner but that's the compromise you have to make to run at 5S.