I've never actually bought a laptop

Why go for those ones though, as low-end gaming laptops they are much clunkier than your laptop would need to be.

surely something like this is way better, way cheaper and a kilo lighter.

https://www.box.co.uk/HP-255-G7_2580199.html

There's nothing in the other machines that future proof them at all to be honest. A slightly better processor, but the i5 8300 and Ryzen 2500U are both modern quad core, eight thread CPU's. The graphics card does nothing to future proof it either.

They are however way clunkier and an entire 1KG heavier, which is 50% heavier more than the HP.

You could get a small 2.5" external if needed? Or else install a 2.5" drive into the laptop yourself. It just seems mad to me to get a big heavy clunker of a laptop for general use, when the reason it's heavy and clunky is something you won't even be using.