Need SEO overhaul done for a family owned fast food diner type restaurant! Should I go with an individual or an agency and why?

We've been around for 40 years. Last two years I started a website (it's kinda shitty but the full menu is available and categorized already), responded to some Google reviews and began using Google ads. My Google ads is very comprehensive (but I need someone who is experienced in Google ads definitely)

I need a pro to takeover. Do you guys recommend an agency or an individual?

I want the full works: web design for SEO and user interface, blogs, other ads and Google ads. And anything else.

I'm looking for someone to get everything done within the first 30-60 days and perhaps manage and maintain on a yearly basis.

PM quotes and brief description of what you will offer me.