I am reporting that I was able to resolve myself.
The key to solving this problem was the "character string".
I assumed that the content sent by P2P was not a "string" but a "number".
It may be hard to see, but I will attach the screen created by UIflow.
I'm an amateur, but I'm glad I worked hard to solve it.
(The attached image is the receiving Atom Matrix)
0_1641013490221_Atom Matrix receiving side.png