Both!
The only difference between an agency and a freelancer is the way they talk about thsemselves.
Design Hero, my 6 figure solo business, is a “micro agency” with only one employee.
But I present as an agency and I pitch at the same level as many agencies with 20-30 employees.
“Agencies” will always be able to charge more simply because of the perception.
You must convince the customer that your size is an advantage.
and it is.
You don’t need 40 ponytailed creatives sitting about on beanbags, eating avocados and playing table tennis…
A small team of experts will usually get a much better result.
The way do it is to be the agency for one speciality,
and you are the individual who runs the agency, with a personal brand as the expert for the niche.
So the answer:
Build an agency brand, but be the face of the agency.
People buy from people, not companies.
For social media, you’ll want a personal brand.
It helps build rappor, and future proofs your brand, by not being tied to one thing.
But branding as an agency will help you charge more, as it lends you legitimacy.
So present yourself as an agency for higher pricing. But be the face of the agency to sell to people