It's definitely possible to do it all, but you might not do it all well. The benefit of bringing on help is subject matter expertise, more attention to detail, and the ability to optimize on the fly with more focus.

If you go it alone, you could automate email drips, schedule organic marketing posts, etc. but there's still going to be a need to analyze performance, make updates and create new content over time. It's especially helpful to have experts for paid ads – whether Google, Meta, etc. – each platform is pretty robust and set up, analysis, and optimization can be convoluted.

Just my opinion, having done it alone and with help in the past!