Even the ThinkPad range has a lot of variation in it and there are lots of build customisation options. I have never had a major issue with ThinkPads on Linux. I tend to spec them quite highly and keep them for many years.

I just bought a new T16 a month ago and it's great (32Gb RAM, sRGB screen, 2Tb SSD, Ryzen 7 processor). Installed PopOS in about 20 mins and everything just works.

However, as others in this thread have observed, I don't really see the point of trying to run local LLMs on a laptop, unless you want to just play a little. If you want to really play with LLMs wouldn't a separate larger box be more effective rather than trying to do it on a mobile device?