Depends on the jurisdictions’ open records laws I would imagine yes they more than likely would be. Presumably if they have such statutes, some jurisdictions have provisions to catch such types “burdensome requests” and either slap a heavy fee for processing such a request and hopefully deter the requestor, or they appeal to a higher court when denying the request entirely

But otherwise if a state has open records laws and you make a lawful request for a large body of publicly available records then I’m inclined to say by definition the clerk is required to provide them provided all requirements of the request are satisfied.