Noises During Shifting problems of the 2015 Nissan Pathfinder

Good day. Since the 1st day of purchasing this vehicle I was experiencing issues with transmission like hesitation, jerking / shuddering / shaking and abnormal whining noise while driving at low speeds. I was not aware about Nissan's major cvt issues until recently. Vehicle's braking is affected because of this abnormal transmission's operation as the vehicle does not immediately stop as needed or requested instead often slipping occurs when downshifting to lower gears. Nissan service center was visited once about a year ago or less. I was told that the software for transmission was somehow missing on the vehicle, without explaining how can a vehicle be manufactured without transmission software. After installing the software, the dealership was unable to pin point what is the problem with my vehicle. I was charged about $140 without being provided a clear diagnose, but was told that most likely the car needs a new transmission. Control valve body was replaced since then, however vehicle drives the same exact way. Please, advise how can get assistance from.