Hi @SaferHarbors,
You should be able to get into acro mode by setting (and using) the mode_acro joystick button function, or by choosing Acro in the mode dropdown in QGroundControl.
Note that like the other advanced flight modes acro has not been as extensively tested as the standard modes. As discussed in this thread it seems there’s at least one known issue with how it operates.
If the stabilize and depth hold modes aren’t working properly there are most likely issues with your configuration (e.g. motor positions/assignments, sensor calibrations, joystick calibration, etc), or perhaps some malfunctioning sensors on your flight controller.