That's what my house does. If I kill the internet, automations still work, as well as the interface via LAN (I've got hairpin NAT set up to make this easier than having 2 addresses in the app), if I kill Home Assistant, all devices still function manually.
I favor ZigBee to WiFi smart devices, although the polluted spectrum in my area gives me some headaches. With WiFi devices when possible I buy premade stuff (so that it's CE compliant), and flash ESPHome on them, or similar.

Indeed, nice and layered.

If internet, wifi, internet, and zigbee/thread/zwave up, fully functional, can close my garage door from miles away

If internet is down, then everything still works within wifi range.

If local connectivity is down, well, all the local controls still work almost the same as a non-smart (the 'on/off' switches sit in the middle instead of being 'on' or 'off' since physical and logical state could otherwise disagree, but switch down to off, switch up to on still works).

I'm oretty certain there is not a single printer on the consumer market these days that works without wifi.