Thanks, Manu!
I'll provide links for references, but if you think about it, it doesn't make sense to use multiple <h1> elements anyway. Why use multiple <h1> elements when you can use one with multiple <h2> elements?
Furthermore, some assistive technology tools do not read the <title> element. So if the first thing they read is the first <h1> element, and it doesn't describe the content of the whole page, it can be confusing, to say the least.
https://www.a11yproject.com/posts/how-to-accessible-heading-structure/#best-practices-summarized