Dual SIM - Saving contacts auto specify desired number

Greetings bazinet15,

Thanks for visiting the Apple Support Communities! It seems you'd like to specify which phone number is to be used when calling a contact with your iPhone based on the email account from where the contacts are syncing.

Specifying the phone number to be used based on the email account isn't supported. However, each contact can be assigned a default phone number. Check out the information in the article below:

Using Dual SIM with an eSIM - Apple Support

"When you call one of your contacts, you don't need to choose which number to use every time. By default, your iPhone uses the same number that you used the last time you called that contact. If you haven't called that contact, your iPhone uses your default number. If you want to, you can specify which number to use for your calls with a contact. Follow these steps:

1. Tap the contact.
2. Tap Preferred Cellular Plan.
3. Tap the number you want to use with that contact."

Kind regards.

The sim doesn't hold your contacts.