The client transmits up to 6 dB below the access point it joined, and 6 dB is the smallest that gap ever gets. It holds at 6 dB only on a 320 MHz channel. At 20 MHz, a Low Power Indoor client sits 18 dB below a Standard Power one, because the ceiling in 6 GHz is measured per megahertz and a narrow channel is legally quieter than a wide one.
The same rule is why a "30 dBm" access point on a 20 MHz channel is capped at 18 dBm, and why picking a narrower channel for cleaner air is a coverage decision you may not know you made.
Settle the channel width first. Then size the cell to the client, because the client is the one that has to answer back.
The full piece walks it end to end: power spectral density and channel width, the 6 dB client backoff and the two different mechanisms behind it, what Standard Power really buys a client at each width, the new Geofenced Variable Power class, and the channels Standard Power gives up to get its power.
Please let me know where I might have stated these things incorrectly...