This is how it works in an agency.
However, here I believe the main issue is that when it comes to SEO, freelancers have very different opinions on what works and what doesn’t.
For example, just recently I had a client who hired an SEO specialist and me to redesign his website. We had very different opinion on what on-page SEO means. The other guy believed that keyword stuffing, annoying popups and backlinks from random sites were good for ranking. I disagreed and refused to design those ridiculous popups that jump in your face every time you open a page.
I would recommend hiring a consultant first.
You need a person who will outline the project goals, requirements, KPIs etc. Once you have a clear project brief you can start hiring the people who understand your vision and build you what you need.
An alternative is to hire an agency