How to install ACR presets into Adobe Camera Raw 2021
WINDOWS - C: Users-UserName -AppData-Roaming -Adobe-CameraRaw -Cameraprofiles.
IMPORTANT -- Make sure you're adding the brushes as separate files, not in their folder. If you add as a folder, they won't show properly. You need to add all the files as separates.
You can now use and access your brush files within ACR by clicking on the little brush preset icon top right.