Sorry for miscommunication, We don't use <ava-player> tag directly, and insert the player using appendChild.
Since you are using <ava-player> tag, you can just use
const playerInstance= document.querySelector("ava-player");
playerInstance.configure({
token: '<AVA-API-JWT-TOKEN>',
clientApiEndpointUrl: <endpointUri>,
videoName: <videoName>
});
playerInstance.load();