My guess is that you put your single SIM into the slot for SIM 2. What does it say when you go to your SIM manager?
That's normal what you see , my Fold 4 has esim View attachment 351611View attachment 351612
I think it gets triggered when using a Esim to show sim slot available, my s23u with Att sim doesn't show thisMy wife's S23 Ultra is also using eSIM with Tmobile and she also has dual notifications (SIM 1 and eSIIM 1). As if the phone has 2 SIMS. I think it may be a software issue. When SIM1 (physical SIM) is NOT inserted, it should not show both SIMS in the notifications sound settings.... Just my thought.