vaultMix2021

I need a software for video mixing setting up the start, fade in, cue (can be more than one), mix, fade out, end. I had done in as3 but its no longer available.. The thing is that in as3, I had multiple layers over the video with graphics which have their own timelines...but now all this is impossible to do with this code. I need it to do it for windows essentially and later on osx. Maybe some one of you have an idea of how to do it. Thanks in advance.