can you use different carriers on dual sim card?

Yes.

Using Dual SIM with an eSIM - Apple Support

Using Dual SIM with two nano-SIM cards - Apple Support

I assure you that you can. In a single SIM card phone, you're locked to one network and will have to remove and insert a different SIM card to use another. But for a dual active SIM phone, you can have two different networks on the same phone and switch between them with ease. That’s the main purpose of dual SIM phones.

From this link: Using Dual SIM with an eSIM - Apple Support

To use two different carriers, your iPhone must be unlocked. Otherwise,

both plans must be from the same carrier. If a CDMA carrier provides

your first SIM, your second SIM won't support CDMA. Contact your carrier

for more information. 



If you have an enterprise or corporate cellular service plan, check

with your company administrator to see if they support this feature.