STM32WB55 CubeMX Configuration

[ASiva.1]

I am building a wireless application (BLE) with STM32WB55CG. For that, I am planning to use HSI and LSE (LSE as RF wake up clock and HSI as CPU1 and CPU2 clock). For that, I disabled HSE in the RCC part of CubeMX. After I did that, RF becomes inactive and unselectable. How can I solve this issue to make wireless application without using HSE? (I am using STM32Cube_FW version 1.8.0)

[ASiva.1]

I was able to get BLE working by enabling external crystal oscillator for HSE in RCC section of the STM32CubeMX. But, I did not use HSE anywhere in the clock configurations. So, I would like to know whether HSE(an external oscillator( is a must for BLE implementation.