On my VF2 board with freshly flashed 202302 image I solved keyring problems by switching to live active repository using the following commands.
Warning: do not use below method if you need to use graphical session!
wget http://ftp.debian.org/debian/pool/main/d/debian-ports-archive-keyring/debian-ports-archive-keyring_2023.02.01_all.deb
apt-get install ./debian-ports-archive-keyring_2023.02.01_all.deb
sed -i "s/^deb/#deb/g" /etc/apt/sources.list
echo "deb http://ftp.ports.debian.org/debian-ports/ unstable main contrib non-free" >> /etc/apt/sources.list
apt-get update
apt-get dist-upgrade
Not sure about side-effects with the stuff from /usr/local…