Just wait, it wasn't until around 5-30 hours before the attacks started happening nearly consistently. When the evolution factor rises to like 0.4-0.6 they start attacking regularly, and when its above 0.7 then its almost constant.
They will also get bigger, build more bases, and yeah.
This is a creative representation of what it was kind of like (though it was a lot bigger than this makes it look) and had way more resources and everything. The black is supposed to represent oil and the red is biters and stuff. It isn't perfect or to scale but I think you have an idea where there were like walls connecting the bodies of water and everything to prevent attacks in the main area. Btw the starting zone was just above those two lakes in the center of the dessert and that dark green is supposed to be coal because I already used black
By the way I did reply to this in my head when I was just waking up yesterday, just forgot to actually type. It was essentially along the lines of 'you lucky f***'. it looksl ike something you made yourself, mental. Flat desert landscape is like an hours' drive from where I am. Constantly having to grenade my way through forests. Urgh