Are you writing a book or are publishing a book? Those are two separate things and if you search up the word authortube on YouTube you’ll get a bunch of people who are looking to publish and not many for fun. And honestly, most of them are not professionals and shouldn’t have their advice be taken.
Writing a draft is not hard and creating ideas isn’t too difficult (the snowflake method is the most popular way to create ideas from a singular idea.) It’s what comes afterwards: revisions (plot, characters, etc.), editing the words, doing those over and over until it is finished.
You don’t need to publish your first manuscript. It’s fine to just write a story or a few for yourself and later on decide if they are ready to go to a publisher or self publish.
Authortubers I like the most are: shaelinwrites, katytastic and Liselle Sambury. The first two both have degrees I think and shaelin is an editor.