Hello.

My employer gave me a S21 5G phone. I use it with a physical SIM in slot 1 and an eSIM. People told me they had problems contacting me on my SIM1 number. I fiddled around with settings.

If i set 'Network mode' (Settings/Connections/Mobile Networks) for the eSIM to '3G only', network quality for SIM1 shows all bars. If i toggle the Network mode of the eSIM to anything else, the quality drops significantly, probably causing, in areas with less reception like in buildings, the SIM1 to have 1 bar or worse.

Roaming, VoLTE toggling etc doesn't seem to influence this. And the behaviour is repeatable (toggle Network mode influences connection quality bars of SIM1).

Anybody have any idea? Is this a design flaw, with 2 radio modules (one for every of the dual SIMs) that influence each other, leading to lower connection quality?