Object animation

Generally I like to make animations in Gifs to post on twitter. I always face a problem, usually each animation has a different time (with loop). I think it would be very good if I could put a loop inside another file with different speeds.
I imagine something like clicking twice on the frame and opening a window where I can make an animation with x time. When you return to the main animation, the square can be another format to represent.

Or instead of this work, it could all be a place in another file.

I am not sure what you are asking, do you need to change the speed of an animation? Because there is an option in the frame menu to change the constant frame rate.

No. I will give an example.
Imagine a character running and imagine the background parallax. The character’s running speed is different from the background.
If I’m not mistaken, Flash used to have this, I don’t know if Animate CC has it.

How long is the animation you are hoping to make… You could move over the different frames into the file you want and duplicate the frames to change/half the speed of either the paralax or the character.