I have the S10e and with one of my SIM cards the mobile network connection breaks down all the time.
It only happens with my Swiss Salt SIM (swapped it already for a new one, same issues). In most cases the phone doesn't even seem to recognize the loss of connection; still shows 4G and tries to load webpages. Switching airplane mode on and off fixes it until it breaks down again after 5-10min.
It is working completely fine with my German Aldi SIM and I've already swapped slots on the SIM tray - no difference. No issues with WiFi.
Anyone experiencing similar issues? Any help much appreciated.