I just got a ThinkPad E14 Gen 6 and the only thing I had to fix/install manually was the driver for the fingerprint reader (fprintd). Everything else just worked, including my docking station and ultra wide monitor.
It helps to look for things that have some level of official backing. Dell has some models for Ubuntu and Red Hat uses various ThinkPads for employee Linux laptops. (Lot more Macs as well when I left but still plenty of ThinkPads that are overwhelmingly Linux.)