Are you genuinely unfamiliar with the folks who launch off on their own into the deep wilderness for years on end. Not only for vanity, but largely to do groundbreaking research?
Sure, individual weirdos can do that for a few years. But you're talking about literally millennia of travel. Hundreds of generations of people living their entire life on the bus never getting to the destination before they die. Trapped out in the cold empty void of space with literally nothing around, for their entire lives, and the lives of their children, and their children's children, for longer than we have had the written word. Never even knowing if the destination is worth it.
We don't have anywhere near the engine technology to make it anywhere worth going to in 400 years. That's orders of magnitude more difficult.
Anywhere that might sustain life is no closer than a couple thousand years away if we develop ultra-efficient almost magical engines that only bend the laws of physics instead of breaking them outright. Stuff like accelerating the propellent so hard that it picks up enormous amounts of relativistic mass, like every gram of propellant weighs effectively a ton because you've accelerated it so close to the speed of light, which requires some kind of ultra-dense power source that makes mere matter-antimatter annihilation look like burning a match.
Are you confusing "adventurer" and "explorer"? There are plenty of contemporary adventurers (motivated by ego, fame, personal achievement) but explorers? Not so much.
Are you genuinely unfamiliar with the folks who launch off on their own into the deep wilderness for years on end. Not only for vanity, but largely to do groundbreaking research?