For client sites, especially in ORM where the pages are often very similar, I would stop treating it as one site-wide content problem and split it before changing anything.
First, segment in Search Console by page type and query: brand/name pages, supporting articles, and location/service pages, and compare the same 28-day period before and after the drop. That usually shows whether it is a handful of templated pages losing ground or the whole site.
Second, check the pages that dropped against the search result, not against each other: does the page answer the specific question behind the query, with something a visitor could not get from the other results — a first-hand detail, a dated update, a named process, evidence — or is it mainly the same intro, headings and filler rewritten? In ORM work that last point matters a lot, because near-duplicate reputation pages tend to fall together.
Third, do not rewrite everything at once. Pick the highest-traffic dropped pages, refresh one batch with a proper brief (intent, what to add, what to cut, internal links to the pages that should rank), publish, note the date and the change in a simple log, then leave it alone long enough to read Search Console properly. If a page is thin and has no distinct job, merge or prune it and redirect, rather than refreshing it for the sake of it.
And with clients, I would set the expectation up front: no reactive edits after every update announcement, one agreed batch, one review point. That keeps you from undoing a change before you can tell whether it helped.