iPhone Mirroring Not Working on My MacBook

My iPhone screen mirroring to my MacBook Air M3 isn't working, and I don't know why. I’ve changed my internet connection several times, and I’m sure that both Bluetooth and Wi-Fi are on and working fine, but it still doesn’t work. Not even once.

I also have an issue with notifications on my iPhone. My notifications don’t appear on my MacBook. Additionally, some notifications don’t appear on my Apple Watch either, even though I’ve reset and erased all data from my Apple Watch once. The problem still persists.

I even switched my iPhone during this process, upgrading from an iPhone 13 to an iPhone 16.

[Edited by Moderator]