Hi, there...
If you are looking for some magic trick to match those requirements wanted by Youtube, there is none. Everyone struggles to get there (unless you are a celebrity). Even those who already there can't give you a shortcut to get your first thousand subs in a week or a month.
It will take time. Even with all SEO knowledge and SEO tools you've got, it will take time.
I suggest you read this one below. It won't make you get a thousand subs in a month, but it will give you fresh ideas:
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