Can you make a laptop and tune by installing better graphics cards and so (mine cost 650 euro)?
No you can't. For laptops, you can only upgrade to RAM or SSDs. Although there are laptops whose graphics card or CPU is interchangeable. However, you can't install even those with more power because of cooling and power supply. If your laptop has a USB-C Thunderbolt connection you can connect an eGPU to it. But I would like to doubt it at an unspecified 650 euro device.
Almost impossible.
There are no graphic cards in a laptop, these are just graphics chips. In addition, motherboards are usually adapted for this one model and therefore have a certain shape.
If you want to upgrade something, then first buy a PC.
That depends on the laptop. In addition, one must distinguish whether one wants to install the graphics card in the laptop or wants to use an external housing.
my cost 650 euro
That's not the question, the question is, is this laptop offered with different graphics cards. If so, it is quite possible that he has an MXM slot, then you can swap.
For an external graphics card, the laptop needs a Thunderbold 3 port, which leads 4 PCI-E lanes to the outside via which the graphics card can work. There are then appropriate housing / docking stations in which one can then install the card.
