As a seasoned veteran player of the MOO series, I used to win decisively when I began playing CTS, but I was quite shocked when I resumed playing after a long time away and discovered that even on Very Easy, the game has become almost if not entirely unwinnable.
Unwinnable games are not fun.
Gradient levels of challenge are fine, but where the [insert expletive here] is the sandbox mode for re-learning and developing new strategies?
What about new players?

I am ready to request a full refund.

That indeed doesn't sound like any fun at all. While MoO CtS does feature a tutorial scenario, it isn't recommended. It is broken and doesn't really teach the player anything better than a regular game. Just like its predecessors, there is a lot of things that can complicate your efforts in achieving galactic domination. Fortunately there is a fair share of strategy guides on the internet that can help the player understand the game. For MoO CtS, you can find a chunky one on GameFAQs that extensively goes through the game's features and mechanics. Additionally, you can also find a handful of articles about the game over at the Steam community's guide category. When struggling with any fundamental thing like economy, diplomacy, research or the military, a guide can help clarifying those aspects.

While at it, I would also recommend installing the Unofficial Code Patch, abbreviated as UCP. It fixes a lot of bugs in the vanilla game. It also does implement a few new features and quality of life improvements. A few examples being rally points, custom autobuild templates, more tooltips and just like in MoO1 being able to close menus with right click.