It seems that you are not struggling with SEO, rather than Project Management.

You should have taks in place and also use a project manager software to keep track of the tasks you are assigning.

You as a owner are in charge of setting up KPI’s and deliverables.

SEO in essence is about Technical, Onsite and Offiste. This sounds easy but in the end if you break each part in different task it becomes diffcult.

When managing a remote team/agency you need to have an overview of the tasks and create deadlines, timelines and priorities each one.

Good luck and sorry for the bad quality. I have faced the same issue but learned my lesson the hard way.