How do I log modified works using promise()

Your code runs asynchronously. The forEach method returns before any of the setTimeout callbacks have executed, so none of your array items have been modified.

You already know that you need to use a Promise to wait for the callbacks to complete:
Using Promises - JavaScript | MDN[^]

You need to turn the setTimeout call into a Promise:
javascript - How to make a promise from setTimeout - Stack Overflow[^]

const later = (delay) => new Promise(resolve => setTimeout(resolve, delay));

You'll need to build up a list of promises, then wait for them all to complete:
Promise.all() - JavaScript | MDN[^]
Array.prototype.map() - JavaScript | MDN[^]

It's probably easiest to use async and await:
async function - JavaScript | MDN[^]

Unfortunately, you can't use await in a top-level script, so you'll need to have an outer function to use it:

(async function(){
    const promises = works.map(async (item) => {
        await later(3000);
        if (item.name === "CCF") {
            item.workStatus.isComplete = true;
        }
    });
    
    await Promise.all(promises);
    console.log(works);
})();

Demo[^]

If you want to stick to using callbacks:

const promises = works.map((item) => later(3000).then(() => {
    if (item.name === "CCF") {
        item.workStatus.isComplete = true;
    }
}));

Promise.all(promises).then(() => console.log(works));

Demo[^]