So, my basic thought here is to give you some ideas about some of these very low cost LED lights that can be make 100% local control with not much work. I have converted a number of these ‘Tuya’ type lights, there are a number of very interesting lighting devices in this space, though note, not all can be make to ‘get off the cloud’. This specific device is not a really ‘nice’ looking, not sophisticated and is on WiFi, which you did not ‘specify’. All that said, it might give you a start and some ideas for a relative low cost (other than your 'mental sweat equity 
) 100% local in home only starting point. Also, there is lots of interesting work going on around these new high gHz motion sensors as well. Adding these into a setup might be interesting (another rabbit hole to go down). Links below :
Good hunting!
Globe Electric Wi-Fi Smart Ambient Night Light with Motion Detection
If you have a Raspberry Pi or similar setup that lets you create a control a ‘separate’ WiFi network, you can convert this USD 20 device to 100% all local with only in software an very easily set of steps:
