Hi. After the removal of Age of Empires III Complete Collection from Steam and the official server shutdown, is there no way to keep the game alive through a Community Patch? I would like them to add all the Civilizations and mechanics of the Definitive Edition, like they did with AOE2.

Someone in the AOE III community would have to step up and do the job. It's possible to play AOE III on Voobly for many years already, however, we were not able to establish a growing community due to lack of interest.

But I would like to make a mod where they add civilizations, gameplay and mechanics of the Definitive Edition. As well as add the Wars of Liberty mod.

I get your point. But we first have to find someone with the required knowledge to maintain the mod and of course developing it. The developers of 1.6 were working on it for almost a full year, before they had a release that could be played on Voobly / that was stable enough so it could be played.

Another problem, you also have to get the community to play it, which really was a challenge and we had to unrate other mods before the community started playing it. In your case, it will be even more difficult, as you don’t even have the player base.