There is a way to do this in Dynatrace. Browse to Settitngs --> Anomaly Detection. Then pick the group for which you'd like to reset (either applications, services, DB services, or infrastructure). Then, near the bottom of the page is a "Reset" button.
Use the Reset button, and not the Reset to Defaults button. The Reset to Defaults button is used to reset the values above to their defaults that come out of the box. If you want to do this for EVERYTHING in your environment, then you should do this Reset on all levels (applications, services, DB services, and infrastructure).