If using zigbee2mqtt with these sonoff dongles note when ordering there are 2 versions. Version P based on CC2652. Version E based on EFR32MG21. The E version seems to work, flashing is slightly different if you are changing from coordinator to router or vice versa. It is listed as experimental on zigbee2mqtt site .
For the time being it seems that purchasing and using the P version is a better choice. We are testing the E version and will publish any specific info here.