Reports

Im facing the same issue, i would love a api that retrieves my user lists.
For now i did some things for javascript.

IMDBListToObject
I made a Userscript that add a button to the page that get all the itens from a list and show in another tab as JSON

Other Method
You can also fetch the html page and scrap the data from it, the problem is that it returns only the first 25 itens of the list and you need to open CORS for IMDB urls in your website.

/*
EN:
https://www.imdb.com/user/ur174614034/ratings/?view=detailed
Other langs, ex PT:
https://www.imdb.com/pt/user/ur174614034/ratings/?view=detailed
The "view" argument is important
*/

fetch("https://www.imdb.com/pt/user/ur174614034/watchlist/?ref_=up_urwls_sm").then(r=>r.text()).then(r => {
    let doc = document.createElement("div");
    doc.innerHTML = r;

    // logs the title of the itens in the list
    console.log([...doc.querySelectorAll(".ipc-title--title")].map(e=>e.innerText))
})

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