You can make a lot of money tech trading even without high diplomacy. You just need a lot of buyers. Buy a tech that a few AIs have and sell it to all the rest. This will let you stay current in tech, it evens out the AIs so no one becomes too powerful, and it makes you tons of money. And you can get a diplomacy advantage by building the diplomatic translators and researching the diplomacy branch of the tech tree, which the AI seems to completely ignore.
Also, ship designing and fleets make combat easier in GC2 easier than in GC1. The AI fleets are usually made of a mix of modern ships and obsolete ships. My fleets are made entirely of modern ships and they win each battle with low losses. Surprise attacks are very devastating to the AI especially if they are already at war. Once you get a military resource, you are truly unstoppable.
I've only got one complete metaverse game in my profile. It was against 9 AIs on a large map, playing as the Drath with default stats. I won by influence, but my early victories were by combat. Influence was just the quickest way to win once I was dominant.
