You have been over thinking this and/or confused by posts about Zero-conf
From most OS (with the exception of some Windows) you can resolve the name raspberrypi.local e.g with ping raspberrypi.local.
To connect via ssh you need to use the correct commands e.g. ssh email@example.com for a normal Raspberry Pi OS.
NOTE Occasionally this will fail, due to ...
The problem is that there is no Audio Sink defined. Check with
rpi ~$ bluetoothctl show
Controller DC:A6:32:7F:38:48 (public)
UUID: Headset AG (00001112-0000-1000-8000-00805f9b34fb)
Please download and flash the image Raspberry Pi OS (32-bit) Lite without any modifications. Connect the RasPi wired to your internet router and boot the RasPi with the fresh flashed image. Then do a ping 126.96.36.199. If it doesn't work then the problem is your network, not the RasPi.
If it works then follow Setting up a wireless LAN via the command line. If it ...
This could be a false positive, but the symptoms (unspecific as they are) match up with the answer I provided here.
In short, it seems some clients fail to connect unless you disable WPA2 with proto=wpa, or wpa_supplicant is replaced with something that provides an WPA2 Authenticator like hostapd.