If the selector lever will not move from P using the proper shift procedure, continue to hold down the brake pedal.

Take the vehicle to an Authorized Mazda Dealer to have the system checked.
Shift-Lock System
Manual Shift ModePower Steering Fluid Line Component Removal/Installation
NOTE:
The following procedure is for replacement of the parts shown in the figure.
Regarding replacement of the suction hose and return hose, refer to the electric
power steering oil pump component removal/installation..
Power Steering Pipe Component Removal/Installation
NOT ...
Camshaft Position (CMP) Sensor Removal/Installation [Mzr 2.0, Mzr 2.5]
CAUTION:
When replacing the CMP sensor, make sure there is no foreign material on
it such as metal shavings. If it is installed with foreign material, the sensor
output signal will malfunction resulting from fluctuation in magnetic flux and
cause a deterioration in engine control.
...
For your information
Main Owner's Manual
This comprehensive Owner’s Manual for the Subaru Solterra has been carefully
designed to cover the full range of models, trims, and available equipment, including
optional features that may not be installed on your specific vehicle. As a result,
you may encounter descrip ...