Open files are limited to 1024, which is quite low. I would increase it, starting with a value around 65535.
Example for php 8.3:
mkdir -p /etc/systemd/system/php8.3-fpm.service.d/
echo -e "[Service]\nLimitNOFILE=65535" > /etc/systemd/system/php8.3-fpm.service.d/override.conf
systemctl daemon-reload
systemctl restart php8.3-fpm.service
Check again that open files limit has been raised:
cat /proc/$(pgrep -f 'master.*php\/8\.3' | head -n1)/limits