According to the DEPRECATION section of the apt-key man page:

Except for using apt-key del in maintainer scripts, the use of apt-key is deprecated. This section shows how to replace existing use of apt-key.

The man page contains some hints and an example how to convert command snippets with apt-key to a supported command.

Deprecated:

wget -qO- https://myrepo.example/myrepo.asc | sudo apt-key add -

Supported replacement:

wget -qO- https://myrepo.example/myrepo.asc | sudo tee /etc/apt/trusted.gpg.d/myrepo.asc

Recommended replacement:

wget -qO- https://myrepo.example/myrepo.asc | sudo tee /etc/apt/keyrings/myrepo.asc
deb [signed-by=/etc/apt/keyrings/myrepo.asc arch=amd64] https://myrepo.example/debian main

Example with raspberrypi.org repositories:

root@raspi1:~# apt update
Hit:1 http://raspbian.raspberrypi.org/raspbian bookworm InRelease
Hit:2 http://archive.raspberrypi.org/debian bookworm InRelease
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
All packages are up to date.
W: http://raspbian.raspberrypi.org/raspbian/dists/bookworm/InRelease: Key is stored in legacy trusted.gpg keyring (/etc/apt/trusted.gpg), see the DEPRECATION section in apt-key(8) for details.
W: http://archive.raspberrypi.org/debian/dists/bookworm/InRelease: Key is stored in legacy trusted.gpg keyring (/etc/apt/trusted.gpg), see the DEPRECATION section in apt-key(8) for details.
root@raspi1:~# wget -qO- http://raspbian.raspberrypi.org/raspbian.public.key | sudo tee /etc/apt/trusted.gpg.d/raspbian-raspberrypi.asc
root@raspi1:~# wget -qO- http://archive.raspberrypi.org/debian/raspberrypi.gpg.key | sudo tee /etc/apt/trusted.gpg.d/archive-raspberrypi.asc
root@raspi1:~# apt update
Hit:1 http://raspbian.raspberrypi.org/raspbian bookworm InRelease
Hit:2 http://archive.raspberrypi.org/debian bookworm InRelease
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
All packages are up to date.
root@raspi1:~#