KYC or Transaction Monitoring, Which is best?

I also searched on the internet and found this post about transaction monitoring (https://www.kychub.com/blog/transaction-monitoring-process/) on the internet

KYC (Know Your Customer) or any KYC and transaction monitoring are both crucial components of anti-money laundering (AML) and counter-terrorism financing (CTF) efforts in the financial industry. Any KYC and transaction monitoring play vital roles in combating financial crimes. Financial institutions typically implement a comprehensive AML program that includes both KYC processes and transaction monitoring systems to create a robust KYC is more preventative, helping to establish the legitimacy of customers before they engage in transactions. I also searched about it here: https://anykycaccount.com/blog/ . 

Transaction monitoring is more reactive, aiming to detect and prevent suspicious activities as they occur. defense against money laundering, fraud, and other illicit activities. Any KYC or KYC helps assess the initial risk associated with a customer. Transaction monitoring helps identify ongoing risks based on actual financial behaviors.