Calls from other dialer apps can also connected using the dial rules, as long as the other dialer app didn't set a specific SIM card itself.
After installation of the app it will run in a demo mode, which will show you which SIM card would be chosen and which phone number would be called if a matching dial rule exists and the dual SIM dialer function would be unlocked. The dual SIM call function can be unlocked with an in app payment once. To make sure the dual SIM dialer function works on your dual SIM phone a trial subscription of 14 days can be activated. (The subscription have to be canceled withing the 14 days trial period or it will also be charged yearly with the unlock price.)