I have spent years fixing WordPress sites bogged down by technical debt. You do...

https://www.pawn-bookmarks.win/why-seo-agencies-see-profit-margins-evaporate-when-scaling-service-delivery

I have spent years fixing WordPress sites bogged down by technical debt. You do not need a big rebuild to boost rankings. Start by adding image compression for speed, adding internal links to old posts, and killing spam with Akismet