Does it make sense to connect an external gtx 1080 to my laptop with a gtx 1050 ti max-Q (expert question)?

It makes little sense because of the loss of performance right?

above all, this is probably not plug and play 🔌➕ ▶

and the graphics improvement in the game is not much better I guess 🧐🤔

It is probably better to tinker with a new pc right away

Do you have too much money and a Thunderbolt connection on your notebook?

Yes

If you have the right Thunderbolt connection and an external housing for the 1080, then that would be a very big upgrade in terms of FPS and possible quality settings. Because PCIe Gen3 x4 has enough bandwidth.

PS: Yes, that's pretty much plug & play.

Then of course you can do that and a GTX1080 has about twice as much power as a mobile 1050Ti

However… I would rather sell the existing notebook and add the price of the external GPU solution and then buy a notebook with an RTX3060Ti. Either comes out the same or even cheaper