Most 5g mobile phones are dual card, only Apple mobile phone is single card. There is no difference between card 1 and card 2 in dual-SIM mobile phones and they can be interchanged. In the past, the card of China Telecom could only be placed in card 1, and the card of China Mobile and China Unicom could be placed in both card slots, but now there is no such difference. Use 5g on one card and 4g on the other. It's very convenient.
Dual card dual 5g mobile phone terminals, some card slot 1, 2 support 5g function, but some mobile phones only card slot 1 support 5g, card slot 2 do not support 5g.
And the previous mobile phone is the same use, a card put a card card two are the same use, does not affect any call function, and Internet function, a card is used to card one, personal habits.