How do I delete ALL Chrome/Google Account stored website passwords at once?

Found it. Clearing all the saved passwords in Chrome from Clear browsing data... also deletes the synced passwords in the Google Account. The setting can be revealed by clicking on the Advanced Tab.

The fastest way to clear all Chrome passwords is with this shortcut:

Ctrl+Shift+Delete

That'll open the "Clear browsing data" window.

Click the Advanced tab, then choose a time range. Choose "All time" if you want to delete all passwords. Click the checkbox for "Passwords and other sign-in data". Click the blue button "Clear data" and then wait:

It can take a long time to delete the passwords and other cached items (it took 20 minutes for my Chrome to clear 1200 passwords and 350MB cached pages/images).

Based on the answer by @bill-mcgonigle I assume it would also be possible to just use the Chrome Console

function sleep(ms) { return new Promise(resolve => setTimeout(resolve, ms)); }
for (let button of window.document.querySelectorAll('div[role=grid] > div[jsmodel] > div[role=gridcell] > div[role=button]')) {
    if (typeof button != undefined) {
        button.click();
        sleep(3100);
    }
}

This worked for me, after the first time you run it, Google will ask for your password again. After that my 200+ passwords were deleted without any issue.

Please note there's a warning in the console to understand the risk of running anything there. Be advised, read the above carefully to understand what you run.

Clarification:

// function to wait for 3 seconds before clicking the next delete button
function sleep(ms) { return new Promise(resolve => setTimeout(resolve, ms)); }
// start a loop iteration of all buttons inside the password grid
// please note there are two grids on the page
for (let button of window.document.querySelectorAll('div[role=grid] > div[jsmodel] > div[role=gridcell] > div[role=button]')) {
    // in my debugging there was one undefined button
    if (typeof button != undefined) {
        // click that exact button element
        button.click();
        // wait for 3.1 seconds
        sleep(3100);
    }
}