Ranking technique

I just wanted to discuss a topic that probably has been beaten to death. An ex client I had in a big USA market, with three brick mortar stores in a niche, decided they need a new change up on the web site end of 2023. Fine. Prior to this I worked with their SEO company and they did the normal or typical white hat, on site SEO. They did some external traffic with Google ad words. I believe that SEO company was let go at the end of 2023 as well. The client had a handful maybe of top rankings on a few good keywords. What’s interesting, is my Google search console and SEO monitoring tools were still tied to the website so I was getting reports all year in 2024. The new SEO company that took over the site, did some interesting techniques to boost the primary landing pages ranking on Google. One of them that I witnessed was they dumped a calendar about 20 to 25,000 pages onto the site. This event calendar had trash in it with Non-relatable content, and links to nowhere. A bunch of the calendar pages were blank but the ones I could dig up had nothing good. Sometimes even had partial broken code on the page lol however, after that Google indexed all of those calendar pages. I noticed the primary Landing pages rose to the top of Google. It took a few months. I am not directly acknowledging those thousands of pages was the primary cause. Although I do agree, the internal link structure spiked as well as the external. Any thoughts on this type of Mcfuckery? TLDR: OP thinks SEO company dumped a calendar with 25,000 pages non-related content onto a site and the site got boosted G rankings.