The nice thing about buying something like that is that you can modify it.

Computer doesn’t fit because this bit is in the way? Chop it out.

Need some more holes in the back? Drill more holes!

This vertical strut is in the way of that other thing & it only fits here because that’s where the mounting holes are? Make some new mounting holes.

The whole thing is 25 mm (1") too deep? Cut 25 mm (1") off the back.