The secondhand X1 probably has more RAM, which you will find very nice - 8 GB on the Macbook Neo is fine for email + web browsing but won't hold up well to heavier use such as programming.

Thinkpad + linux is unbeatable in my opinion. My daily driver is a more than 10 years old W540 and absolutely rock solid, drives three monitors, has four USB ports and a GPU. I don't use it for gaming or anything like that, just software development, work, email and browsing. It is maxed out for RAM and cost all of 300 bucks or so second hand.

Are you sure you want to start a CompSci / PoliSci degree program if you're financially strapped?

There are many cheaper options than the Lenovo, depending on where you are located.

The latest Mac Neo will likely outperform an older laptop on every metric. Battery life will be the thing you notice more than any other as you go to classes for the day. Linux has always been behind in this regard. You can always spin up a cloud vm for pure linux if you need to, and more likely than not the university will have labs and other linux resources that are free.

Used computers are a better value. If you want an Apple, I'd buy a used macbook over new, and a used thinkpad is just awesome, it's a really nice machine and will serve you well. I would go with the thinkpad. Also check out Dell outlet for refurbished and scratch and dent, I've bought from them several times. https://outlet.us.dell.com/ also back market: https://www.backmarket.com/en-us/p/lenovo-thinkpad-x1-carbon...

When I was a student, I almost exclusively bought used computers online and generally had positive experiences, and never had a bad experience. It's not like a car where you need a professional pre-purchase inspection, it's pretty easy to check.

If you are going to get a used computer, check the remaining SSD life, remaining battery life, and inspect the screen for dead pixels. Lots of sources online for how to do this. The advantage of refurbished is this is taken care of for you.