I noticed, in the nixos-hardware link , that services.fstrim.enable for Dell XPS 13 9310 but not for Lenovo T480s. I understand that the option allows better use of the SSD is that correct? Despite being different manifactures, they both have SSD. Why this discrepancy?
Yeah it looks like that profile is intended to be a starting point and has been minimally maintained by only one person, who does enable fstrim elsewhere in their configuration.
I’d recommend submitting a PR to add at least common/pc/ssd.