I would connect the following external graphics card to my laptop.
https://www.ebay.de/...4014395095
Is it possible to get close to the maximum performance of the graphics card with an adapter?
800 is a rip off, don't buy the card.
Do you even have an interface on your laptop that enables a corresponding speed?
Where can I find or recognize this?
You will not be able to use the full power. So much in advance.
Your laptop needs a Thunderbolt port and the graphics card needs some kind of housing. E.g. Razer Core X.
Alternatively, a mini PCI connection on the laptop is also possible. But that's already fiddled too much.