I am in the same boat.
Lenovo Z50-70 bought 2015. 8 GB RAM upgraded to 16 GB recently. It has got 4GB Nvidia graphics, does mild AI stuff as well. Hard Disc replaced with Samsung SSD few years back. Full HD screen. I even bought a 4K-27 inch monitor to connect to it last week. Thought it struggles to play beyond 1440p. Win10 works and is totally responsive. I hope it keeps going for 3 more years. :)