Or one can read recent research papers that thoroughly document the incredible fragility of the existing NTP hierarchy and soberly consider their recommendations for remediation:
https://www.ndss-symposium.org/wp-content/uploads/ndss2021_1A-2_24302_paper.pdf
Or simply use non-Internet NTP servers based on a Stratum-0 GPS source for mission-critical network timing.
Until then, we may all wake up one morning and discover massive data breaches traced to an unfounded reliance on insecure public NTP servers. Then the game truly will be over, but not in our favor.
-mel