Would you recommend using either a freelancer or a boutique agency for an existing (WordPress) website project with a development arc / technical debt that spans 5-6 years? What are the pros and cons for each, and which option would you ultimately recommend?

I have a WordPress website that needs a new technical steward... The website itself is built on the WordPress tech stack and has been in development for 5 years...

I am currently looking at a number of freelancers and boutique agencies... With that in mind, which variant of the long-term technical steward would you recommend - freelancer or boutique agency? Why?