Hi @quantum,
If you are destroying the existing hierarchy on scene change, and loading a new one, a good way to persist data is in a global object.
A common trick is to add it under the browser window
object.
For example:
window.Score = {
coins: 0
};
Now in any script to write to that you do:
window.Score.coins += 3;
To read from that value:
const coins = window.Score.coins;