For example there might be a wormhole that takes you to a different destination if you fly through it backwards. You're very unlikely to find that out by chance, but if you explore you'll find a thing that tells you (probably behind some other puzzle).
Great game.
I'm not saying ending was perfect, but I can't think of a better way of ending it.
The game is 2 million light years wide, but a meter deep.
There's the Kerbal Space Program approach, where space exploration is tough and you need to learn a LOT to succeed at it. The tradeoff of this is a high sense of accomplishment, where simply landing and returning from another body feels like you did something incredible.
There's also the Outer Wilds approach, where the story carries it. Moving around isn't hard at all, but you have specific goals to accomplish that move you towards a final ending. Diversity in how you accomplish those goals makes it feel fresh.
Mass Effect is similar, where you have some freedom to explore, but it's again in the pursuit of this broader story. So exploration feels like a rich side quest more than the main point of the task.
Or alternatively Scavengers Reign
Personally I want spelljammer. Baldurs Gate meets Sea of Thieves in space with 80s killer clowns
There is so much drama that can happen there and the scale is the least of it.