Key is stored in legacy trusted.gpg keyring (/etc/apt/trusted.gpg), see the DEPRECATION section in apt-key(8) for details.

Error:
W: https://repo.mongodb.org/apt/ubuntu/dists/jammy/mongodb-org/6.0/Release.gpg: Key is stored in legacy trusted.gpg keyring (/etc/apt/trusted.gpg), see the DEPRECATION section in apt-key(8) for details.

One line

for KEY in $(apt-key --keyring /etc/apt/trusted.gpg list | grep -E "(([ ]{1,2}(([0-9A-F]{4}))){10})" | tr -d " " | grep -E "([0-9A-F]){8}\b" ); do K=${KEY:(-8)}; apt-key export $K | sudo gpg --dearmour -o /etc/apt/trusted.gpg.d/imported-from-trusted-gpg-$K.gpg; done

Expand

for KEY in $( \
    apt-key --keyring /etc/apt/trusted.gpg list \
    | grep -E "(([ ]{1,2}(([0-9A-F]{4}))){10})" \
    | tr -d " " \
    | grep -E "([0-9A-F]){8}\b" \
); do
    K=${KEY:(-8)}
    apt-key export $K \
    | sudo gpg --dearmour -o /etc/apt/trusted.gpg.d/imported-from-trusted-gpg-$K.gpg
done

Source