OK, digging for the Lenovo ThinkPad T480 data sheet (which is not linked from their main website, at least in a place easily found), I gathered:
* their main product page -- https://www.lenovo.com/us/en/laptops/thinkpad/thinkpad-t-ser... -- does not list anything about SATA;
* (BTW, the support page linked from the main product page, is pointless and doesn't provide any data sheets; and the downloads page, has countless files, none of which contains "data" or "sheet" or "spec" in their name;)
* the user manual -- https://download.lenovo.com/pccbbs/mobiles_pdf/t480_ug_en.pd... -- says that SATA is "available on some models", not specifying which;
* the maintenance manual -- https://download.lenovo.com/pccbbs/mobiles_pdf/t480_hmm_en.p... -- doesn't even list the word SATA (or NVMe), however it does seem to present in the "Internal Storage" section something which resembles a HDD tray;
* the "platform specifications" (found via Google) -- https://psref.lenovo.com/syspool/Sys/PDF/ThinkPad/ThinkPad_T... -- says <<system has one HDD slot or one M.2 2280 slot exclusively for storage>> and <<installed M.2 SSD is PCIe 3.0 x 4 but run at PCIe 3.0 x 2 due to M.2 SSD adapter limitation>>, which I interpret as: perhaps you can put either an M.2 or a SATA drive, however even with NVMe, you're still running at SATA speeds;
So all in all I'm a little bit disappointed about how "transparent" Lenovo is...
Can someone please confirm if the SATA port is available regardless of how the laptop was bought? (I.e. even if initially bought with a NVMe SSD?)