For AoE2:HD, whenever I want a game like this, I always just put each player in its own team. I bet that would work with AoE1:DE, too. (I think I started doing that long ago because of the same issue you describe.)
I don’t know why or if it’s needed in AoE1:DE, but it sounds like it is, based off your experience. You’d think not specifying any teams should mean, “Each player is against every other player,” but explicitly specifying it should hopefully fix things.
There may be a chance that if you always have the highest (or lowest) score among all players when the game matures, maybe they all just globally target you as a product of their algorithm? In AoE2:HD when I play 2 Human vs. 2 AI, I notice they usually target me first because I have the highest score on my team. Or, on occasion, they try to take out the the lowest score teammate first.
In AoE2:HD, sometimes I’ll do a match using me (Team1) vs. 2AI (Team2) vs. 1AI (Team3), where two AI are teammates with “Original AI” skills, and the other AI is on his own team but stronger AI skills (i.e., specify “AI” instead of “Original AI”).
- In this case, Team2 teams up and has to fight me and the Team3 AI, while Team3 AI has to fend for himself and conquer all.
- Or in can sometimes be fun to team up with an AI, too.
You can make some neat combinations by specifying teams like this in AoE2:HD, and assume it can be done in AoE1:DE.