Change format when uploading animation to YouTube.

Fellow Adobe animate users,

I would like to eventually upload my animations to YouTube. However, I have read on other sites that the best two options for format size are either 1290*720 or 1920*1080.

Now, I would like to change my stage size, which is currently height: 550. width: 400 (550*400), to one of the abovementioned sizes. However, I would like the content (so all my drawings, etc.) to change along with the stage, so that not only the stage (or scene panel, whatever one likes to call it), becomes larger while all drawings & animations stay at 550*400 in my case.

I already tried it once when I clicked on "scale content" as well, but only the stage became bigger, while all the content inside just stayed the same size.

So, to conclude, are 1290*720 and/or 1920*1080 the right size formats for Youtube, and is it still possible to change both my stage/scene panel along with all its content to another, (larger) size.

This would help me out a lot, therefore thank you in advance!

Kind Regards.