How to get rid of the second sim card?

Question

Mobile devices

Hello!
I have two SIM cards: the first one is for calls and SMS, the second one is for all sorts of secure things, such as SMS banking, password recovery on a djimail, which, in turn, is tied to other secure things, etc. Also, sometimes they call the second SIM card (she is almost 15 years old, many old contacts do not know the new number, which is only a few years old), but I myself do not call from her, I do not send SMS (to avoid stealing the number in the operator's service center knowing the latest outgoing calls).
Before that, I always used dual-sim state employees, first on the Nokia platform, then on androids. It's time to buy a new phone, but the trouble is that you have to become attached to dual-terminality. The range of top smart phones for two SIM cards is very poor, support for these phones by the manufacturer is not a fountain, since there are at least a minimum of users.
Question: how to get rid of the second sim card? The operator has support for call forwarding, but SMS forwarding works only within the network (Kyivstar). I don't want to carry a second phone. There is a perverted idea: to keep a cheap android mobile phone at home, on which to install a call forwarding application. Are there alternative options?

Answer 1

Buy Sony Xperia Z3 Dual SIM, why is it a bad option?
And a separate device for the second SIM card is also quite a viable option.