Hum, I’m not sure this should be recommended but I managed to get it back up by restoring the updater-generated backup and relaunching updater.phar.
rsync /var/www/nextcloud/data/updater-oc1a2tpaodei/backups/nextcloud-28.0.1.1-1709714266/ /var/www/nextcloud/ -av
sudo -u www-data php --define apc.enable_cli=1 /var/www/nextcloud/updater/updater.phar
sudo -u www-data php8.2 --define apc.enable_cli=1 /var/www/nextcloud/occ upgrade
sudo -u www-data php8.2 --define apc.enable_cli=1 /var/www/nextcloud/occ maintenance:mode --off
sudo systemctl restart php8.2-fpm.service
See you at the next upgrade 