YK is mostly right, except that it's not simultaneously in the literal sense because you cannot send packets on different frequencies at exactly the same time. The packets are sent with a small delay in between them which can vary depending on whether you are sending scannable advertisements or not, and if you are then it also depends if a central device sends a scan request to which the stack will respond to with a scan response.
More info in the Bluetooth 5.2 core spec, Vol 6, Part B, section 4.4.2.
This advertisement data is not conformant with the standard. For that reason the scanning devices are probably dropping it because they don't know how to display it. You need to create properly formatted data which follows the standard.
-) I would like to add the possibility of debugging (from the outside) of my target board. To do this, I would like to add ISA3, MINI, CORTEX connectors to my target board project, and connect these lines to EFR32BG13.
Why would you need all 3 connectors? They have redundant functionalities between them. We recommend using just mini-simplicity as it should have all the functionality you need (SWD, PTI and VCOM).