> I want to play the game, but I don't want my stuff getting destroyed if I do a subpar job of defending it.
You're looking for "peaceful mode".
I've played on both peaceful mode and normal settings. The advantage of biters existing is that they act as a check on runaway expansion and encourage you to move to cleaner energy sources. When you replace coal plants with solar or nuclear, you'll find that biters aren't annoyed by your base so much.
I played my first couple of games on "peaceful mode", and played one on non-peaceful (in order to get the achievements for completing the game without solar power & lasers).
There's .. enough complexity to the game such that I can see it'd be better to start with non-peaceful.
Comparing non-peaceful mode to peaceful mode, a bit more of your time goes into setting up and maintaining defenses; but once a good set of defenses is established, playing is ~roughly~ the same as what peaceful would be. Peaceful is fun. Non-peaceful is also fun. But the powerful weapons at the end aren't as enticing on peaceful as they are on non-peaceful.
The developers explained the rationale in an old blog post. Basically they were able to see through playtime statistics that people playing in peaceful mode gave up at a higher rate than non-peaceful, because they didn't feel that pressure to keep improving things.
You're looking for "peaceful mode".
I've played on both peaceful mode and normal settings. The advantage of biters existing is that they act as a check on runaway expansion and encourage you to move to cleaner energy sources. When you replace coal plants with solar or nuclear, you'll find that biters aren't annoyed by your base so much.