T480 also has dual batteries with one being removable. I upgraded the top cover to magnesium, added WiFi 7, upgraded to 32 GiB, swapped from a HDD to a SSD, and changed the motherboard from i3-7300U to the i7-8650U. The only repair I ever did was replace the screen because I messed up once and dropped it. Oddly enough, it supports an eGPU over Thunderbolt 3 and 25W TDP unlocking so it was once used as my compact gaming machine. Mine also has 3 spare extended batteries and a custom external charger for them.
replyT480s and T490 are inferior compared to the T480's usability of ports and batteries.