MacBook – Stop tilde and grave acting as deadkeys on French Macbook Pro keyboard (AZERTY)

I have a 2015 Macbook Pro running Mojave where internal keyboard is French AZERTY (ISO) type as shown here:

Pressing grave (the key next to return) or tilde (Alt-Gr n) act as a dead keys.

Input stops until the next key is pressed in case I want to type ã,ñorõ after ~ or à,è,ì,ò,ù after `

Is it possible to map these so they do not act as dead keys – so pressing ` results in output as in line 1 not line 2.

I have tried installing Karabiner and making a script based on their examples but I can't find something to map the key to.

In my test script below (which doesn't work) the "from:{key_code" "backslash" is what Karabiner-EventViewer shows when I press ` (which is where \ is on US keyboard).

The "to:{key_code" "51" (or grave_accent_and_tilde) is what Karabiner-EventViewer reports for the < key on my keyboard and was just picked as a test.

{
  "title": "Convert deadkey ` to a grave (`) (AZERTY)",
  "rules": [
    {
      "description": "Convert deadkey ` to a grave (`) while leaving £ accessible.",
      "manipulators": [
        {
          "from": {
            "key_code": "backslash"
          },
          "to": [
            {
              "key_code": "51",
              "modifiers": [
                "right_option"
              ]
            }
          ],
          "type": "basic"
        }
      ]
    }
  ]
}

I've seen various questions asking about where the keys are or how to swap them but not how to stop dead key acting as such.

Is this possible in any way using Karabiner or otherwise?

I considered changing keyboard layout to UK and then mapping back every single different key to French location but would rather not if there is a better way.