Random physical SIM failure and network crash in iPhone 12 Pro MAX

Sometimes, averagely once a day and anyway as soon as I enter “Settings > Mobile Data”, while loading Mobile data usage statistics about my Primary Mobile plan, my Physical SIM (my Primary mobile plan) fails and restarts the network. Then after a few seconds, if I’m NOT in ROAMING my Physical SIM comes back working properly, but if I’m abroad in roaming, it takes more than 2 minutes to come back working, which is a real nightmare! See the picture below.

I have already tried replacing/ changing both my active Physical SIM and eSIM, cleaning-up the Physical SIM slot, hard resetting my iPhone, performing Setting reset and Network reset, but the issue is STILL there.

In Apple Store we performed several HW diagnoses and they resulted at the very beginning negative, but suddenly positive after cleaning-up the Physical SIM slot, that’s why I suspect an HW issue… but maybe it’s just a coincidence and it could have been caused by some SW bug… so far I’m really confused.

Has anyone any idea about how to fix this super annoying (especially whenever I’m abroad) issue?