Welcome to the Wyze User Community Forum @jade55! 
There is no direct adjustment for the length of cloud recordings on Cam Plus. The recordings continue until no more motion is detected, up to 5 minutes.
The indirect adjustment is in the Cam Sensitivity. With it maxed out, not only should there be more motion activations, but the length of the recordings should also be prolonged as the threshold for motion detection is increased, thereby allowing for the slightest motion to continue the recording upload. A lower sensitivity should theoretically shorten the videos.