Q:
"which Mac is worth investing in?"
A:
NONE of them.
They are all commodity items that begin to depreciate the moment you take them out of the box.
Some will last longer than others.
Just pick the one that seems best-suited to your needs, buy it, and use it.
If you make money from your use of it, depreciate it as an asset.
But as an "investment", it's not the Mac that "makes money" for you.
YOU will earn the money, from your own talents... using it as no more than a tool.
OK, lecture over.
Of the two you posted, for video editing, there is no comparison.
The 27" is superior.
You will NEVER regret having that larger display, especially for editing video.