On top of that, metrics can have exemplars, which give you more (and dynamic) dimensions for buckets without increasing the cardinality of the metric vectors th

On top of that, metrics can have exemplars, which give you more (and dynamic) dimensions for buckets without increasing the cardinality of the metric vectors themselves. It's pretty much a wide event, with the sampling rate on this extra information just being the scrape interval you were already using anyway. Not every library or tool supports exemplars, but they're a big part of the Prometheus & Grafana value proposition that many users entirely overlook.