You can buy a cordless phone set that will pair by Bluetooth with your cell phone and then you can use those cordless phones to connect with your cellphone when you are at home as well as using them for your home phone. It will ring for incoming calls off either. There are many available, depending on the number of home cordless phone extensions you want and features - similar to the VTECH below - (I have no experience with this particular phone - just as an example).
VTech - Connect to Cell DECT 6.0 Expandable Phone System
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