I'm new to this game, first played demo then got all, inc. TA aswell, bla bla...

I started with Yor Collective, found it really hard then got used to it. I was able to build an immense economy at the very beginning, soon needing some tech trading as I wasn't able to obtain any economy improvements... Anyway, then I wanted to try Terrans.

I started with these bonuses: Influence and Diplomacy maxed out. Then I started playing a really BORING game with Terrans. I focused on yellow techs (generally +diplomacy, +morale and +influence). Now I think I have over 230% diplomacy and I just trade techs for ridiculous prices, even I wasn't able to research at the beginning, I traded techs over and over (I was giving 1, taking 3+money ) and now even I was the worst at the beginning (economy-research-etc) now I'm dominating the world. My question is, is it all the time same for Terrans? I mean, max diplomacy, start trading. And I've made alliances with 8 out of 9 major empires. So, no one is attacking me aswell. Even I conquered 2 of my allies with influence starbases (with 290 influence on them, was putting a fleet of constructors next to their planets, then creating starbases, within 5-10 turns, they were falling to me, even they weren't getting aggressive???).

By the way, difficulty is crippling. Fortunately, I started nearly at the center of the universe (immense universe, rare habitatable planets, many stars, abundant asteroids, etc... also max minor races), so that I was the central trading civilization. Even, my tax rates were lower than my trade, so when I researched master trade etc, I gave them to other civilizations to boost my trade indirectly (I was their best partner ).

And finally, my final question is, I found Terrans easy, is there any recommendations for Terrans to make game complicated? Also, to have fun&struggle, which civilization should I choose? Thanks!