As MarkFW said, the new Ryzen's don't work the way that you are expecting given your experience with Intel CPUs. Try using this command with a light or mixed load:
sudo watch -n 1 cpupower monitor
You should see the CPU frequencies bouncing all around between the stated frequency steps from the Linux kernel and should see even below the lowest frequency listed though that's probably because the core is slipping into C-states rather than being in P-states. Modern AMD CPUs take much more control over their own frequency behavior as controlled on the chip itself compared to older AMD or intel CPUs and they can be very dynamic in their frequency scaling as well as very fine in their frequency steps (as mentioned down to 25 MHz steps). I will use your own quote but change the bolded words,
the table of available frequencies (if the set of supported P-states is not a continuous range)
So rather than fill a frequency table full of 25 MHz steps, they list a few basic frequencies (min, max unboosted, and 1 or 2 mid frequencies) and then will adjust between them, over them, or even under them though the OS governor may be calling for only one of the specific frequencies.
You can try using the cpupower tool to set or modify the listed frequencies but I have no idea if it will really work on Zen2 CPUs. If you are trying to set a specific CPU frequency, you're best bet is to do so through the BIOS. If that is not possible then you may have a lot of headaches trying to get it done through P-state overclocking (or underclocking) within Linux. It may already work, I don't know, I don't have a Zen 2 CPU to try it but you'll definitely want to be on a recent kernel and hope the support is there even though Zen 2 CPUs are relatively very new.
Good luck.
Edit: Some links for reference,
Linux frequency scaling, governor setting, and frequency manipulation
wiki.archlinux.org
P-state clock adjustment tool that was made for Zen1
www.phoronix.com