Yes, I do understand the issue with the aspect ratio, which is indeed good design, but parent comment's example is that "you can run two apps side by side" is the tautology. Well, at least since the invention of double-entry bookkeeping and getting rid of Archimedian phone design.
The missing piece that makes it not a tautology is that two apps side by side have the same aspect ratio as one app full screen (but 90 degrees rotated)
No, you can't, unless the apps are designed for different aspect ratios.