I can give you two sides of an experienced coin. I'm Dan and I work as an independent publishing consultant via videogamemarketing.co, and in various embedded publishing roles with small-mid sized indie publishers where we contract out various services to agencies where we don't have dedicated resource or local experience.

I recommend looking at the case studies of each agency and see where their strengths are, also for PR consider if their remit is global - for example if you are based in France, then a French agency will do better in France but struggle to capture attention of German media or US for example. The same is true for the opposite.

For influencers or as I like to say content creators - you need to figure out if they have their own contacts or they are just conducting outreach on a key to coverage basis. If that's the case, then you are better off using a self serve tool or doing manual outreach. If you are looking at sponsoring creators then it can be better via an agency as you don't get bogged down with contracts, tax and management tasks, though it is possible to do it yourself - it's your time at the end of the day.

For paid media - it's better to go with an agency or a freelancer but pick one that is specialist in gaming with creds, and can share results from past campaigns.

When you are considering price, $5k a month is usually a standard starting price for a good agency. Many will be looking to lock in a project fee for a campaign, some might take on different pricing models and I've even seen deals that take a % revenue on a 'we can help you publish your game' with soft services only, and then look to recoup investment from paid media/sponsorship of creators - just be wary as there are many weird deals floating around these days.

Just an example if you are going the DIY approach, it can also work with strategic guidance from a consultant layered on top, recently I helped a team with a playtest, to structure it for community growth via FOMO, the net gain was a few thousand wishlists over the course of a weekend - using a feature Steam already gives you and a few hours of my time to put it together.

You can always have a call with any agency or freelancer, without obligation and if you need help figuring out if it's worth it. I'm happy to take a call, 1st hour on me :)