1) You can always save the modified OOB dashboard as a copy, as the OOB dashboards serve as examples and users can still customize them for their use cases. You will find a copy icon next to the dashboard title, allowing you to save the modified dashboard as a copy.
2) Regarding the source regex pattern that includes "Infrastructure," is it by design. Suggestion: update the source name to be generic from "SuperDomain\|.*\|Infrastructure\|.*" to "SuperDomain\|[^|]*\|[^|]*\|[^|]*"