The Zohar states that Hashem is not a creator. It's infinitely beneath Him to be a creator and creating a universe is, k'vyachol, completely out of character for Him.
During the 6 days of creation, Hashem created. However, on day 7, He stopped creating, which means He was simply Himself. This is why Shabbat is so holy.
Hashem's goal in creating was so that He could invite us to be with Him (as it says in Derech Hashem, Olam Haba is Hashem's community living with Him in an eternal state of intimacy).
That's why Shabbat is me'ein olam haba. It's the day of the week where we join Hashem at His eternal table. It is the day of the week where Hashem is Himself, and our goal is to reach Him not while He working, creating, but join Him when He is being Himself.
The purpose of all creative activity is to create something that one can enjoy. Creativity is so fun though, we can get lost in it and never sit down and enjoy what we created, we'll just move on to the next project. This is not the right way to approach creativity.
The way we keep Shabbat, therefore, is the blessing for everything else in existence. If we are keeping Shabbat properly, it means we have the right approach. We are creating for 6 days, but we aren't making the creating the point, we are making the result the point. Hashem is getting His "someone else" to join Him, and the purpose of the 6 days of creation is being fulfilled, so therefore He blesses another 6 days of creating for another me'ein olam haba day.
I hope that makes sense. There are sources for all of the above easily found in much of Chabad Chassidus.