Please refer to the following link.
The MG24 is limited by firmware to BLE power from -3 to 8 dBm.
Designed for 20dBm output, the MG24 is inefficient and requires significantly more current consumption than the nRF52840 for the same 0dBm output.
Have you measured the current in active mode past the advertisement, when the device was connected already?
After connecting, the nRF52840 consumes some current to wake up at regular intervals to check the connection, even when it is not transmitting.
The MG24 will continue to consume current unless explicitly put to sleep.
(This is only the result of using the current BSP2.2.0.)
Considering future development, I would recommend getting ppk2.