My current personal laptop is a ThinkPad 13 2nd Gen. I believe it was released in 2017. It was my work laptop for 4 years and was gifted to me by the employer. During those 4 years as a work laptop it proved its worth---9 hours of teaching per day plugged into a projector. Once it was mine I slapped Linux on it. Today, the battery still lasts 10 hours.

So, definitely look into getting something used. You probably don't need the best of the best. If I had to choose right now I would rank my needs and try to get something close enough.

An i3 or equivalent might be fine, and i7 might be overkill. Something with an i5, perhaps? Lots of people say 8GB is the minimum for RAM, my computer has 6GB and works. But, if I were going to buy today I might take 16GB just as future-proofing. I would also need that USB-C.

Browse around sites like https://linux-hardware.org/ before purchasing to make sure you don't get any surprises.

Speaking of surprises, I would take anything with Nvidia just in case, and whatever model I take would need to be reparable or upgradable.

If you decide on buying new, you might as well take a look at the vendors mentioned by other users. System76, Slimbook, Framework, StarBook, and so on will hurt your wallet a bit, but at least you know the hardware won't result in time lost troubleshooting.