question

Not sure about the Phantom-S but the US2000/US3000 also don't show that because it is not transmitted by the battery.

I'm certain that this is something on the Pylontech side.

I originally had three US3000C modules and I did not see the cell information either. Like Matthias said, this information is not being transmitted by the battery.
A few weeks ago, I went out a procured a fourth US3000C module and installed it. It ended up being the master module by default due to my rack layout. Being a newer batch it probably has newer firmware and the cell information is now showing, although only the cells in that module, not my older ones.
Probably need to update the firmware in the older modules, but it needs a dongle and some sort of unobtanium software, so I have not paid much more attention to it.

I managed to get an MS windows copy of the Pylontech software "batteryview.exe" from Pylontech support.

You then need an adaptor - USB - RS232 and cable, to communicate to each battery using the "console" RJ connector. This then gives usage full data of long term battery behavour and also allows the setting of the real-time clock of each battery which I would suggest you do, so the data collected aligns with the correct local time.

I have problems with UP2500 batteries in the details menu of Victron connect which gives the cell voltage (reversed) and cell temperature(very wacky giving 10C increments output data for every 1C actual), fortunately, everything else works as intended. Victron reported after investigation the incorrect data is coming from Pylonthech batteries due to firmware issues.

hope this helps.