Can I use 2 SIMs at the same time?

Yes, you can use your physical SIM for calls and SMS and the DENT eSIM for your data needs - if your device supports Dual SIM. 
Many eSIM capable phones, e.g. Apple iPhone 11 Pro or Samsung S20, support Dual SIM. This allows you to have your physical SIM and your eSIM active at the same time. iPhone model 13 and higher support 2 active eSIMs at the same time. 

Please check whether your phone settings and software versions support "Dual SIM Standby".