The cheapest local supplier offers used Lenovo Thinkpads X series with 2y warranty, but they have 12 inch display. It seems too small. And other Lenovo thinkpads with 15.6" display are L570 or Yoga series. And they all come with i5 2 processor cores only (and windows preinstalled). There's an option [1] Lenovo thinkpad E15 gen2 with AMD 4 cores, and the supplier told it is a better option than Dell in terms of durability.

[1] https://psref.lenovo.com/syspool/Sys/PDF/ThinkPad/ThinkPad_E...