You obviously haven't searched for it
It supposed to work as described on that page. If your phone has no built-in call recording function, then it has to be rooted if you want to record calls from the phone line.
Try the following settings:
Try to allowlist Unlocker to to able to auto-start in background: https://dontkillmyapp.com/oneplus
adb shell pm grant org.skvalex.cr android.permission.READ_LOGS