I have never read that levels are bad for syrians, only that they shouldn’t be counted as “floor area” when discussing cage sizes. And that they’re bad for pairs of dwarfs.
Like Serendipity I like shelves for stability, I use an Ikea Knagglig box for all my syrians which works as a platform/large nest box underneath. Takes up quite a bit of a bin cage but all the space underneath and on top is useable.
I just finished sticking the leg back on this platform actually, it’s a cheap IKEA shelf with craft dowels stuck on as legs. Previous ham built the bedding up underneath and had a huge nest. The little fence isn’t necessary at all I just had a lot of time on my hands when I made it
