The Third Person Argument

The argument goes like this:
1. X is beautiful
2. Y is beautiful
3. Beauty itself (the idea of ​​beauty) is a real thing (in the modern sense of the word, i.e. independent of human cognition)
4. But, the beautiful itself(a) is also beautiful
Conclusion, x, y, and the beautiful itself (a) take part in the idea of ​​beauty (the beautiful itself (b))
5. But the beautiful itself(b) is also beautiful
 
and so on and so on
 
I don’t understand what kind of argument this is, it seems like a bit of brain fog. It’s clear that the beautiful itself is beautiful, but it’s not beautiful in the same way that a certain object is beautiful, it’s beautiful in its essence (and not just as a feature), it’s not the same sense at all
 
Where am I wrong (or maybe right)?