This is not remotely a safe assumption. We know interstellar travel is resource intensive, but it's within the capabilities of todays technology. It was probably doable with some effort with 1960s technology.

This is the same basic error of reasoning where people say because the moon landing happened, faking the moon landing was also possible (it wasn't: video editing technology of sufficient capability did not exist - space flight and CGI are two entirely separate lines of technical problem solving).

It’s not within today’s technology to actually visit an extrasolar planet. We could possibly do a flyby with a solar sail but we don’t have a way to slow down and enter the planet’s atmosphere. And even that only gets us to the relatively small number of stars that are in our immediate vicinity in any kind of human-civilization-scale timeframe.

Space is 3-dimensional and astronomically, cosmically huge. Getting from a planet to space is trivial compared to getting from space to a planet.

You said you don't think aliens and magic should be the same category, but now argue that they'd be so advanced that, would it even be differentiable from magic?

It would be differentiable in the same way any more advanced technology than what we have now would be. It will have been created through scientific research and engineering, just like our own technology. Not understanding how something works doesn’t make it magic.

> It will have been created through scientific research and engineering, just like our own technology.

It seems a touch hubristic to assume that an advanced civilization with technological capabilities far exceeding our own would have used our processes and techniques to get there.

They’d have their own processes and techniques, but on some level they’d have to be discovering the properties of reality, then using that knowledge to create vessels that could travel between stars, slow down to visit planets, and do various other tricks that seem to defy physics as we know it (based on UAP observations). To me that’s still science and engineering even if it was done in completely different ways.

If I met a wizard, he'd obviously be way better at magic than I am, and it'd be way beyond my understanding of physics. Those safe assumptions don't make magic exist