Compatible GPU

Any eGPU will be bottlenecked by the use of an internal card in a slot designed for low-bandwidth network adapters, plus reduce your system to a pile of disassembled parts -- you won't be able to close up the system with all the internal cabling required (there's no internal space for it), and you'll need an external monitor (the external GPU won't feed the internal display).

Keep the notebook for portable use and buy a desktop system if you need a better GPU -- you will lose the former and end up with the latter, at a huge performance sacrifice even if you can get an external GPU to work -- and that's very much open to question as to whether you can.