Try this : https://en.wikipedia.org/wiki/Project_Daedalus

Also, I agree that the idea for interstellar travel has some holes. Let me rephrase my argument as follows : for every accomplishment of mankind (airplanes, spaceflight, moon landing, nuclear, computers, internet), there have been just as many critics claiming that it isn't possible (they had their own set of reasons). And all of these technologies were much more infeasible compared to interstellar travel (and yet we did that).

5 years ago, would you have imagined ChatGPT or Stable Diffusion? Tech moves fast. There is no doubt in my mind that in a century, we will see interstellar travel like we do airplanes today. But this may well be wishful thinking because I really want this to be true.