How can I make a UI mask that fades in and out?

I need to make a UI mask that is capable of fading in/fading out. I found out the hard way that regular UI masks can’t do this(my fault because I didn’t read the last line of this page).

How can I do it? It doesn’t have to work like a regular mask either. It can work like a mask shown on the video on this issue(in fact I’d prefer it this way).

You can’t fade a mask in/out, no

What is the expected result for fading in/out a mask?

If it’s to fade in/out the elements under the masks, you will have to do that manually with all the children elements with a tween that loops for all the element components under the mask and changes opacity.