>I think I want a stratigic multiplayer co-op game based either on battle or logic or both.

From this description, I get a similar feel of the Halo Wars games or Strategic FPS games like Ready or Not.

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>I think the theme I want is high quality and "tech" effects or child-like gameboard theme (Like Mario or Manopoly)

That's a good start, having a theme can give you an idea later on how to design the models etc.

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>I don't think I am capable of making a game look good and feel good,
jsut the logic sadly. I am into scripting and programming. I am learning
a effects and modeling in blender. But I think this is all too much for
1 peroson to manage. I think that is my current my problem.

And that is fine, you don't have to make everything by yourself, well you can but that will take more time than having a team where everyone has their designated job to do.

Modeling in game development comes near the end phase of game development, since there might be sudden changes you want to make or have to make. Most game developers use placeholder objects and make the gameplay first. For coding the actual game you should look around and talk with other game developers for advice since I have no experience myself in this field.