A regulation is based in law- compliance must occur. A standard is based in simplicity by unity- if it’s done collectively by the composite, it will be easier for all included. Best practice is elusive with no governing body suggesting it, how can any practitioner be sure of its truth. And so best practice usually is bespoke. For x kind of enterprise, or y kind of team- best practice is alpha. When offered such customization, the only means with which to find custom best practice is through baselining.