“Lofi” as it is understood nowadays is more about background music that aims not to be distracting when working/studying. Basically lofi == “lofi (to study to)”.
Trip-hop like Portishead does it, while it is “low fidelity” (as in it uses warm tones, crackling, record scratching, etc), it is not lofi, in the same way that Sabaton is Rock but not Rock&Roll.