Site does not recognize text sent from my auto fill extension. Is there anything else I can try?

I'm new to javascript and writing extensions. I have a content script that fills out "N/A" in a few fields on a site I use for work. Here's what it looks like:

chrome.runtime.onMessage.addListener(
    function(request, sender, sendResponse) {
        try {
            document.querySelector("#anchorInvArea_2 > td.layout-column > md-input-container > div.md-errors-spacer > div").innerHTML = '3 / 5000';
            document.getElementById("Note_2").value = "N/A";
            sendResponse({status: "Success!"});
        } catch (error) {
            console.log(error)
            sendResponse({status: "Exception occurred!"});
        }
    }
);

Here's my manifest:

{
    "name": "LBOT",
    "version": "1.0",
    "manifest_version": 3,
    "icons": {
        "16": "1.png",
        "32": "1.png",
        "48": "1.png",
        "128": "1.png"
    },
    "action": {
        "default_popup": "ext/index.html",
        "default_icon": {
            "16": "1.png",
            "32": "1.png",
            "48": "1.png",
            "128": "1.png"
        }
    },
    "content_scripts": [
        {
          "matches": ["<all_urls>"],
          "js": ["content.js"]
        }
    ],
    "permissions": ["activeTab"]
  }

So you can see here, I'm not only filling "N/A" in a box, i'm also attempting to register a character count increase, hoping the site will recognize and accept my input. It does not accept my input. I have to manually write N/A overtop of the already inserted N/A (inserted by my extension) and then it works. I can't figure out why it doesn't work. Is there a better way to do this? or something else I can try?