@Bartje Okay, so I had a “quick” play around and got the basics working 
I set a div wrapper for the spinner to cover the entire screen. I asked Chat GPT to use Alpine JS to hide the spinner when the page is loaded (as we have that JavaScript framework in Elements). At the moment it’s set to three seconds for testing; however, you just need to comment out the top line and uncomment the other line (I hope that makes sense).
Here’s the updated spinner project file for you to use.
I know we make Elements (and I’m biased), but I love playing around with this stuff. It’s so much fun. 