Increase the number of BLE Bluetooth connected devices for ESP32

[Sirius]

Hello, when I used arduino to increase the number of Bluetooth connections of ESP32, I found that the maximum number of connections can only reach 4, which is not consistent with the official document that the maximum number of connections is 9.
I changed the time the four devices I could connect to send data so they could staggered the data without blocking the channel, replaced the antenna, added more memory, and expanded the Bluetooth space, but unfortunately the fifth Bluetooth device still couldn't connect.
I want to realize that ESP32 can connect 9 or more BLE devices through arduino, how to realize it?

[chegewara]

With esp32 you can connect max 7 ble devices.
Arduino BLE library may have limit, which does not apply NimBLE library.