Improve Google search results for Wordpress site

Natural medicine school website is a Wordpress site, mostly using Elementor but some less important pages are still old school wordpress pages. It is a large site, with class offerings, numerous articles, password-protected online classes, news, etc. The site includes basic Yoast. It had good organic SEO from being widely linked to for many years, but since the AI boom our Google results have slid and it's time to improve SEO for Google and AI. We used to be on the top half of the first page of Google for our niche, and we would like to get back there. It's important that the SEO doesn't read as spam to real humans, as our customers are generally very AI-averse and will consider us poorly if anything sounds fake or like a robot wrote it. Any page edits should be done through elementor. We are not open to changing menus or links within the site itself, that has caused navigation issues with the site in the past. Please tell us how you would approach this project, how the results turned out if you've done this before, and what you think we should know starting out on this kind of project.