I have both a Lenovo X1 Carbon Gen 9 and an HP EliteBook 840 G6 running Linux, I'm very happy with both machines. The HP has a better management of fn keys, seems to lack support for > 4K 30 Hz on its HDMI port with my screen (both that might be fixed on newest generations), the X1 has a better trackpoint handling. Both have fantastic battery life (around 10h) and are quiet. The X1 tends to spin the fan earlier than the HP, if it's an issue, setting the energy profile on "power save" in the KDE battery widget fixes it. Of course it makes the computer slower but it's still quite fast (the CPU is a Core i7-1165G7)
Make sure you avoid hardware that have issues with the camera on Linux, it's a shame we are back to have to check for this stuff.
We bought a number of Carbons (Gen 9) to the office and all of them (5) have had some kind of technical problems. It's been malfunctioning fans, a motherboard that stopped working, a screen where colors were awful etc. We might have gotten a bad batch but it was not at all what I expected from Thinkpads. Lenovo's support has been great though.
I work for a big tech company with thousands of developers. We use Lenovo X1 laptops (Carbon and Extreme) and have been doing that for a few years now.
There is no systemic issue with those laptops. The failure rates are very small.
Same, everyone at our office have had issues with their Carbon. Most other Lenovo's work well, though.
Main issue most had is it chokes whenever doing something video related, which was a bit of an issue during the pandemic. And if you power it through your monitor, it will disconnect and re-connect the screen regularly. Ironic, since the monitors were also from Lenovo.. This made it impossible to have two monitors connected, since you were forced to use one of the USB-C sockets exclusively for power or it would behave erratically.
Make sure you avoid hardware that have issues with the camera on Linux, it's a shame we are back to have to check for this stuff.