I always buy a Windows laptop, boot Ubuntu in it (no install), test everything, and if something doesn't work as-is, i return the laptop. After a decade doing it, no support issues. Except for energy management, which has always been terrible, if any. But that's not easy to test, and, from what I hear, it doesn't seem to be any good in Linux anywhere.
Incidentally, my current laptop is a 600€ Lenovo. You can imagine what I think of frame.work prices.
The cheapest laptop I found that carried an SSD out of the box 5 years ago: Lenovo Ideapad 320.
The display is terrible, no proper graphic card, and I seriously think I should have upgraded the 8GB of RAM the first day, but it still works like the first day. RAM aside, I don't need anything more.
Oh, I see: you want a Thinkpad...
@jgg I don't know what I want. I want to not regret my purchase, and I want to pay little enough money that if I regret my purchase it's swallowable.
I totally get it. Each time I have to renew a gadget I hate the process more.
So last time I was extremely cheap an lazy and went for the cheapest minimal option.
If you go for the minimum, and it goes well, you know you got it right. If you go for the expensive option, and it goes well, you will never know: maybe the cheap option would have been enough.
But who I am to say. I am planning to buy a Fairphone soon, anyway. Out of ethical reasons, of course, but out of sheer lazyness, too: not having to choose another phone in a DECADE? I want three!!
But really, I wouldn't pay much attention to Linux compatibility lists. I never look at them, and I have only found one laptop in which something didn't work.
YMMV, but if you don't go too fancy, Ubuntu is very good handling hardware.
My laptop has the very first 8th gen i5, bought just out of the oven, so I seriously doubt anybody at Canonical had tested it when I installed Ubuntu on it. And here we are.
@jgg Which lenovo model is the 600 euro one? Looking over the thinkpad models I'm struggling to find anything under $1000 USD