I do have a hack rf one just not unboxed (for a while it sounded like UK might ban SDR sales so preemptive buy).
I was under the impression that the spectrum is quite large relative to what you can look at with a waterfall and thus would take forever. Based on your comment sounds like I might need to take another look!
You might also want to take a look at "RF Explorer Spectrum Analyzer"; nice handheld devices with varying frequency ranges - https://j3.rf-explorer.com/