But that would be a
hypercube, not a tesseract, wouldn't it? (seeing as a tesseract specifically refers to a 4D hypercube).
The entire problem with the DBT being a tesseract (or a hypercube) is... well... the great repository of discarded timelines, from which The Time Devourer will reach out and bring death and destruction, is just a fancy box. It seems rather anticlimatic. A higher dimension in general I can understand, but a fancy box?
In the words of the immortal
Kuni:
"You took the box! Let's see what's in the box! ... Nothing! Absolutely nothing! STUPID!"
Still, that might be the way it is.