I have a second-hand Thinkpad T480s that I love, I bought it for 250$ on ebay and replaced its battery because it was fried (+40$). I use it for school and it works flawlessly, around 8h of battery life in a well-configured OpenSUSE Tumbleweed. According to the specs sheet it shouldn’t be, but for some reason it is noticeably lighter than a friend of mine’s MacBook Air 2021.
What I really love about it is the ThinkDock Ultra (iirc 30$ on ebay), which lets me place the laptop on my table, and by just sliding a piece of plastic, it connects all of my peripherals in a second. I love this laptop so much that I’ll use it until it dies so hard that it can’t be fixed at all.