I have little faith. I aggressively replace digital things (does it have a radio and/or compute) that are not actively supported by the manufacturer. I make thoughtful choices about when to trade security vs convenience (I have no home assistant devices. I do have a Google Pixel, because it is supported and receives monthly security updates.) Limit how much collateral damage can happen when it will happen. Have robust offsite versioned backups, a unique password for every system, strong 2FA, credit freezes, etc.

It isn't perfect, but it works for me.