How to make this script resume execution after page reload?

Preliminary context sharing

I am asked to manually perform a very repetitive action on a website that I do not own and for which I do not have any API access.

The only hope I have to automate these actions is to write some JavaScript and execute it on the browser just to automate the actions that I would be doing manually otherwise.

Please sorry in advance if this question already has an answer somewhere else, I'm a backend developer and in my limited knowledge of front-end I didn't manage to find any equivalence.

Explanation of the issue

Say I have to post several entries, one by one, into a form. I have written the following code (over simpified just for demonstration purposes):

//This array of Json objects is produced by an upstream service
var inputs = [
    {
       ...
    },
    {
       ...
    },
    {
       ...
    }
]

for (i = 0; i < inputs.length; i++) {
    fillSomeForms(inputs[i])
    clickSubmit() //<-- this will make the page reload, and so the script execution stop
}

The problem that I have here is very basic: after the first for iteration, when I invoke clickSubmit(), the page reloads (because the submission is a POST followed by a redirect to a "submit next" page) and so the JS stops executing.

I have tried to look around on the web for similar issues, and I've seen people tweaking the localStorage in order to resume the execution of their script.
However, that seems to assume the script being a resource of the front-end code, which is not the case for me (I don't own the code, I simply inject this JS into the browser's developer console and execute it to save some time).

Is there any way to reach this purpose? I am not necessarily looking for a clean solution, just for something that could get this work and spare us some monkey work (nothing of what I'm doing here is clean, but the system administrators do not want to provide access to the REST APIs that the platform actually provide to do so).

When you inject into the console, load a copy of the page into an iframe, and submit your forms from that copy:

const inputs = [ /* a convenient inputs array */ ];
const pageCopy = document.body.appendChild( document.createElement( "iframe" ) );
pageCopy.addEventListener( "load", () => {
    //The page copy has finished loading / reloading, let's submit more stuff
    if( inputs.length > 0 ) {
        const moreInput = inputs.pop();
        console.log( "Submitting inputs: ", moreInput );
        //this shouldn't work, but let's clone the current DOM into the iframe...
        pageCopy.contentDocument.body.parentElement.innerHTML =
            document.body.parentElement.innerHTML;
        fillSomeFormsInPageCopy( pageCopy.contentDocument, moreInput );
        pageCopy.contentDocument.querySelector( "#submitButtonId" ).click();
        console.log( "Clicked submit. Will wait for iframe to finish reloading..." );
        //Okay, we clicked and the iframe is reloading. This event will fire again as soon as it's done reloading, ready to submit more form data
    }
    else if( inputs.length === 0 ) {
        console.log( "Finished submitting all the inputs in the array!" );
    }
} );
pageCopy.src = document.location.href;

Please understand I can't test this code. (I'm not even sure the click() event can be fired across an iframe boundary, for security, but I hope it can.)
Hopefully you can understand how to use the pageCopy's document to find your form elements and set their values. E.g., you can use

pageCopy.contentDocument.getElementById( "form-entry-id-1" ).value =
    moreInput[ "form-entry-id-1" ];

In case it may help someone in the future, I finally was able to work around the problem by opening a new tab (and working in that tab) per iteration of my loop.

Something like this:

while (inputs.length > 0) {
    const singleInput = inputs.pop();
    const newWindow = window.open('about:blank', '_blank');
    newWindow.addEventListener('load', () => {
        newWindow.document.body.parentElement.innerHTML = document.body.parentElement.innerHTML;
        fillForm(newWindow.document, singleInput) //<-- the function fill form uses the document in parameter to perform the different get/set
        newWindow.document.getElementById("submit-button").click();
    });
}