“Structural issues” are not a concern in general on any RV unless it’s sustained some damage Water or otherwise.
Wiring plumbing and components are mostly similar across most rv brands and models.
Buy one that isn’t on the verge of being overloaded due to being under designed and one that feels like the interior hard pieces are pretty solid.
And the box end of a class A or C is the same basically as the box and what’s in it on any trailer frame.
You sound like you’re getting paralysis by analysis here.
Also buying used is a good indication of overall fit/quality. If it’s been towed around 1, 2, 5 or 10 years and has held together chances are it will keep holding together.