The GPU is a permanent part of the system board.  The 1060 was the top option for this model, so there is no way to upgrade what you have even with a system board replacement -- if you need better video, you need a new system.  
I have a dell g5 15 5887 and the 1060ti is bad nowadays. I wonder if i can switch my graphics card somehow to a new better one or is that impossible on a laptop. Ive searched and seen that dell has a method to switch the grapichs card on their laptops?
dell g5 15 5887 graphis card