>>rtpg+(OP)
I had a X1C bought early 2018 and it had great battery life. And I generally was happy with it. Unfortunately it got stolen (luckily I had full disk encryption). Without much investigation I took a X1C again. This time it was a 7th gen. It had HiDPi display which was a bit of pain to have all apps working with a satisfactory resolution and the battery life is much poorer than before. I would take my older one back right away if I could.
Edit: The author uses an 11 year old machine. Not a surprise it works well. With all the new stuff the vendors introduce difficulties are much more common. I hear a lot of complaints from colleagues with Thunderbolt docks, the newest Intel camera generation has no Linux support, not that much has changed. Whether it's 2 steps forward and 1 step back or the other way round is debatable.