How to determine that all widgets are loaded?

Hi everyone!
I need to determinate that all widgets on a page are loaded. How can I do it?
Maybe window.RM has some methods? I couldn’t find it, unfortunately.

I don’t like window.RM.viewerRouter.mag.currentPage.loaded, because it might be too long.
I also don’t like a solution with setInterval(). I have many widgets and I don’t want to use it for each one.

I need help) Thank you for your time!