Lenovo will release firmware updates for Linux users even on systems that don't officially support Linux (though, it can take a while). But I guess that's one of the exceptions that proves the rule
Is it?
Last time I tried to use t480, which is listed as officially supports Ubuntu, I had to use rather ugly hack to fix CPU throttling:
https://github.com/erpalma/throttled
It affects other models as well and not fixed up to this day (at least not by vendor)
Lenovo had a post in their blog acknowledging it, but after some time it mysteriously disappeared
EDIT: Lol, there are HN post about this "fix" happened few hours ago:
https://news.ycombinator.com/item?id=35025838
By quickly checking comments seems like better solution is already available: