Making a chrome extension edit a website's script

There's a game called "duelingbook.com", it's a yugioh sandbox game, and it has hidden features that unlock themselves if you have a named card, but obviously as a sandbox game it's not locked at all, but instead it's UI locked. I tried to make the following extension and no amount of iteration allows me to override the "findCard" function to unlock all features to commit actions faster ( except for "Question" which locks you from checking your graveyard )

What I want is an extension that mimics pressing CTRL + SHIFT + I, and writing there the contents of contentscript.js, which works flawlessly. I am using Edge, but I imagine they are identical.

manifest.json

{
    "name": "Page Redder",
    "action": {},
    "manifest_version": 3,
    "version": "0.1",
    "description": "Turns the page red when you click the icon",
    "content_scripts": [
    {
        "matches": ["https://*.duelingbook.com/*"],
        "all_frames": true,
        "js": ["contentScript.js"]
    }]
}

contentScript.js

function findCard(arr, hand, grave, like)
{
    
    var cards = [player1.m1, player1.m2, player1.m3, player1.m4, player1.m5, player1.s1, player1.s2, player1.s3, player1.s4, player1.s5, player1.pendulumLeft, player1.pendulumRight, player1.fieldSpell, player2.m1, player2.m2, player2.m3, player2.m4, player2.m5, player2.s1, player2.s2, player2.s3, player2.s4, player2.s5, player2.pendulumLeft, player2.pendulumRight, player2.fieldSpell, linkLeft, linkRight, player1.skillCard, player2.skillCard];
    if (hand)
    {
        for (var k = 0; k < player1.hand_arr.length; k++)
        {
            cards.push(player1.hand_arr[k]);
        }
    }
    if (grave)
    {
        for (k = 0; k < player1.grave_arr.length; k++) {
            cards.push(player1.grave_arr[k]);
        }
    }
    for (var i = 0; i < arr.length;i ++)
    {
        if(arr[i] == "Question")
        {
            for (var j = 0; j < cards.length; j++)
            {
                if (cards[j])
                {
                    if (cards[j].data("face_down"))
                    { // Question
                        continue;
                    }
                    //if (cards[j].data("cardfront").data("treated_as") == arr[i] && !cards[j].data("face_down")) {
                    if (((cards[j].data("cardfront").data("treated_as") == arr[i] || like && cards[j].data("cardfront").data("treated_as") && cards[j].data("cardfront").data("treated_as").indexOf(arr[i]) >= 0)) == false)
                    {
                        return false;
                    }
                }
            }
        }
    }
    return true;
}