Is building a long range wifi antenna to connect to the up and coming starlink internet possible?
Starlink doesn't use WiFi, so you won't be able to capture WiFi from it. If you had the right antenna and electronics (which you certainly do not given the cost), you could see the RF signal. You wouldn't be able to decode it however.
If you want to do amateur radio, there are lots of lower frequencies being used on ground and in orbit. These are much more accessible with affordable electronics.