I'm trying to get a corporate website redesigned, the only caveat is that I don't want the developers to use WordPress. I would instead prefer that a static site generator like Jekyll or Hugo is used.

This seems to be a big sticking point, as after a few quotes and a couple of one to one meetings, the response I am getting is:

"We are a WordPress shop. It is the only and best solution. Using a different technology would be a one-off, meaning more cost to you as we would never use it again for another client."

Given previous experience using freelancers that (generally) aren't around to support the site on an ongoing basis, my company would rather use an agency to do the job. Is there an agency or similar that can deliver a project like this?