The value of an audit is in the sequencing, not the finding count. A three-hundred-item report with no priority order is a way of transferring the hard decision back to the client. Ask for the top ten items ranked by expected impact against effort, and for the evidence behind each — a crawl export, a Search Console screenshot, a log sample.
Audits go stale. A site that ships weekly will have invalidated part of any audit within a quarter, which is why a one-off audit with no implementation support so often ends in a PDF nobody opens. Budget for the fixes at the same time as the diagnosis, or buy a smaller audit scoped to the problem you already know you have.