Ooh, this is tough one.
I found a really useful list breaking down ton of sub genres, and exactly what you describe doesn't seem to be there.
https://www.scifiideas.com/posts/a-guide-to-science-fiction-subgenres/
(Unless the aliens are invading or being hidden by the government...)
A name for a genre just for surviving and colonizing new worlds doesn't seem to exist either, and that's one of my favorites. What you're asking about though is that I usually think of as "first contact" stories, if I'm understanding it right.
I'm sure others will have book recommendations, but I'll just suggest watching a classic 70s movie called Close Encounters of the Third Kind.