They just didn't have a 15" metal case in the price range so I got a plastic 16". Overall performance is lower than comparably spec'd HP Z-Book Fireflys I was using, when this Thinkpad T16 G4 hits the upper limits of RAM, it feels like it's using swap on a slow platter drive. Even on lower-spec HP Pro & EliteBooks, they slow down at max RAM but don't just freeze. Our staff thrashes the shit out of gear, so finding decently-priced lower-spec metal-bodied laptops is essential.
Even on latest HP laptops I am able to replace RAM, batteries, SSDs without dealing with epoxied sockets. Haven't had to often, but displays and keyboards could be swapped if absolutely needed last time we had to several years ago. That said, the performance of onboard HP Bluetooth sucks compared to others I've used and their stock bloatware is terrible.
Specific to Lenovo, when I was shopping for a bunch of laptops about 3 years ago there were weird gotchas like "I can get every spec I need EXCEPT backlit keyboard, which kicks me up to the next model, at least $300 more/unit" and "Gee, they solder in a low amount of RAM on this one to make you...yup, spend at least $300 more/unit"...