Ideally process mining is where you would start…as task mining/task capture is more about the keystroke level frontend details that you would want to capture
Generally when process mining is done it is done over a range of process across one system so that we can analyse multiple streams in that system and from there identify the specific areas and yhen concentrate on them
If the process are more manual driven with multipel people…then going with task minging makes sense as it shows the same process being done in different ways and that would help in streamlining the processes and then come up with an automated solution
Cheers