The most recent Lenovo T4x0 or T4x0s (a thinner version) that you can afford. Add more memory and a larger ssd disk as needed. There is nothing wrong with used 3-4 years old machines. Processor power hasn't increased much. Just check the screen resolution, and factor in the extra cost if you need to add memory and swap the ssd disk. The 440 series from 3 years ago didn't have physically separate mouse buttons on the…
T5x0 - for a 15" Laptop
X2x0 - for 12" Laptops ( avoid the X2x0s)
W520, w530, P50, P51 - Desktop replacements 15" size