Is there any difference between the main SIM card and the secondary SIM card in the Redmi Note 14 Pro+ 5G?

The Redmi Note 14 Pro+ 5G doesn’t support SIM primary and secondary card distinction.
For your reference, here is more information about SIM primary and secondary card distinction:
1. The primary and secondary SIM cards in dual SIM smartphones allow using two different mobile network connections in the same phone. These SIM cards can be used for voice calls, text messages, and mobile data;
2. Primary SIM is often the default for calls, messages, and mobile data unless you change it. Secondary SIM provides flexibility and can be used for additional calls, text messages, or data functions. You can switch as needed;
3. If the phone does not support SIM primary and secondary card distinction, it means the phone cannot automatically or easily assign certain default functions (like mobile data, voice calls, or SMS) to a specific SIM card. In such cases, both SIM cards are usually treated equally without a clear distinction of a "primary" and "secondary" card.