SEO What realistic expectations should I have?

Why is SEO so elusive? I'm new; I know, to SEO and over the last few days Iv'e been looking into it. Idk what to expect at all, I'm not even sure if I will be ranked anywhere, how long does it take to get ranked if I do everything I can to increase my ranking with googles algorithms?

If I do Ranking factors like Keyword research, Correlations, Domain authority, Surveys, Links, Site speed, Branding association, Audience research, Good page time and optimized on all devices ect.

I don't even know if what I'm doing is right, it changes so often and the information I'm getting is kinda old.

How long would it take me to rank realistically as a total beginner?