PR is a great weapon for the right product /company and time. OK perfectly you'd be Elon Musk and announcing your new anti gravity device and press lines up. But I will assume you aren't Elon (yet) and though you might find your story compelling it might not be "anti gravity' level exciting to the press.
SO Whether you use an agency or not, the key to real PR success is look at todays HOT news items - the press is searching for stories that fit into TODAYS hot news.
How do you, your people, your product, your company, your service fit into todays hot news.. it doesnt have to be direct fit - but can you create an interesting unique angle...

IE today:
* Macy closes 125 store = doesnt have to be about retail but could be about people, employment, training, locations, culture, old v new, ecomm, brands, .... etc...

* Coronavirus outbreak = doesnt have to be about Rx and cures or masks, but it extends to people, culture, HR, travel, work place, virtual meetings, economy, ....

Just see the press as hungry lions, and you just need to convert your thoughts into red meat ;-)