A possible gameplay loop for those averse to combat, raids, and kill boxes.

[Liwet]

Just put some time into a game called Cliff Empire.  One mechanic in the game requires the player to periodically deliver random resources to an orbital platform in space.  If you fail the task, you lose money (another resource).  If you satisfy the task, you level up.  More mechanics are introduced to the player as they level up.

Now apply this to Rimworld.  The lore is that the Empire will protect your colony from raids but you have to satisfy certain requests of theirs every so often (such as at the beginning of every year or half year).  They'll send a ship to your colony and you have a couple quadrums to satisfy their request by putting goods into the ship.  At the end of the period the ship will fly off (and can also be sent early if you meet all the goals).

If you completely satisfy the request, you unlock something that you didn't have access to before.  Maybe you get access to a new plant or unlock the ability to research a new technology.  Maybe you can also get some minor rewards like a bunch of devilstrand or a new colonist.

If you don't complete the request, you get punished.  This would be the only time you face a raid but it would generally be smaller and not something that would require a kill box to defeat (remember, players in this mode really don't want to deal with raids).  The difficulty of the raid can be decreased by how much of the Empire's request you satisfied (so if you only delivered 50 berries instead of 100, the penalty will only be 50% as bad).  Other penalties can include blight, psychic waves, toxic fallout, eclipses, etc.  These might last for a quadrum or 2 but you could caravan the remaining goods to an Empire city to stop it early.

[Cardbo]

I like this idea.  I would suggest that filling the Empires requests be more openended.   If the Empire requests 50 plasteel, but there is no plasteel on the map, they might be statisfied with 100 regular steel, or 20 components.  Something like that.   Also, if you miss a tribute, it doesn't lead to an immediate raid, but it will drop the Empire's opinion of you, and if it goes low enough, they might withdraw their protection and leave you vulnerable to raids.