Can't access element defined in plugin outlet with DOM interface

Development
3

Would I do something like this?

<script type="text/discourse-plugin" version="0.8">
    api.modifyClass('component:plugin-outlet', {
      didInsertElement() {
        this._super(...arguments);

        const button = document.getElementById('vic-button');
        console.log(button);
      },
    });
</script>

When I do this, there is a repeated null output to the console. I’m a complete newbie so I just tried to search around on meta for people doing similar things, so this is probably not the right track.