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You need to understand the scale of what you are proposing here.
In case you can't read it (it's a bit small), the text in that screenshot says that the mod Beyond Skyrim: Bruma, which is roughly the size of a largeish Skyrim hold, and modifies virtually no existing Skyrim content, contains approximately 195,000 individual records. This is not counting the BSAssets.esm file, which contains another ~9,000 or so records. This is probably a lot smaller than the mod you describe in your question.
For comparison, vanilla Skyrim itself contains a whopping 920,000 records just in Skyrim.esm, and there are more (though not nearly as many) in Update.esm and the DLC files. All told, the Legendary Edition easily contains more than one million records in total.
A "record" is any of a large number of different kinds of data which make up the game. For example, each individual piece of armor is made up of two (usually) records, the ARMO record that describes its gameplay statistics, and the ARMA record that tells the game how to render it when worn. Some records, like Global Variables, are very simple, while others, like Quests, are fiendishly complicated. But, regardless of the specifics, a human being had to sit down in front of the Creation Kit and create every single one of those records, one at a time, by hand.
Now consider all of the other work that needs to be done on a large mod:
Creating textures, meshes, and other art assets
Level design
Writing
Papyrus scripting
QA
Voice acting
Playtesting
And probably half a dozen other things I've forgotten about
The Creation Kit work is the easy part - that's just wiring everything together!
Realistically, it is improbable that you will be able to do all of this work by yourself, with or without the Creation Kit. You should either scale back your ambitions or find a group of like-minded modders with more experience (who may be able to help you learn more about the modding process).