Does selecting a color profile calibrate my monitor?

No. Selecting a color profile tells macOS how to interpret the display's color response. It does not measure the screen or prove that the selected profile describes it accurately. BetterDisplay can select installed profiles, but that selection is not a measurement-based calibration.

Calibration adjusts the display toward a chosen brightness, white point and tonal response. Profiling describes the resulting behavior so color-managed applications can translate colors for it. A calibration system uses a measuring instrument and software. Depending on the monitor, corrections can be applied in the computer, in the monitor's own lookup tables, or both. The ICC's display-calibration explanation describes these different paths.

Choose the monitor's intended picture mode first, then use a profile appropriate to that mode. A profile made for a different mode or panel may be inaccurate. For measured work, keep the display settings consistent with the state used during calibration. Later brightness, contrast or color adjustments can change that state.

P3 does not require HDR. Display P3 specifies a color encoding, including its primaries, white point and tonal response. Enabling HDR is a separate choice about the display's luminance range and presentation. A “P3” label alone does not establish that two screens have matching brightness, tonal response or calibration. See the Display P3 specification and HDR.

In BetterDisplay, use the display's Color Profile menu to choose a profile or open it in ColorSync Utility. See Color Profile for the available operations. If a custom profile causes a black image with color-table adjustments, follow the custom-profile compatibility guidance. Replacing a measured profile with a generic one can change the calibration result.