Ulimit settings doesn't applied (when I log off/after a while)

I have a bash script that creates IPv6 proxies using 3proxy. It works just fine. I wanted to add a new function called rotating. Basically, this rotating mode adds IPv6 addresses to the network interface and changes configuration file of 3proxy every n seconds. If I (log off/wait some time) after I activate this module, the proxies aren't working after the changes. I'm guessing it's about system limits that aren't being applied. How can I fix it? I have left my script below:

cd /home/proxyolusturucu/cronisleri
rm -rf /home/proxyolusturucu/cronisleri/ipyapici$IPV6SUBNET.sh
cat <<EOF >> /home/proxyolusturucu/cronisleri/ipyapici$IPV6SUBNET.sh # This one creates a bash script to create random IPv6 addresses
#!/bin/bash
rm -rf /home/proxyolusturucu/cronisleri/ipolustur$IPV6SUBNET.sh
echo "#!/bin/bash
IPV6=\"${IPV6}\"
IPV6SUBNET=\"$IPV6SUBNET\"" >> /home/proxyolusturucu/cronisleri/ipolustur$IPV6SUBNET.sh
echo 'ipv6_k=(1 2 3 4 5 6 7 8 9 0 a b c d e f)
ipv6_olustur() {
    ipv6_ver() {
        echo "\${ipv6_k[\$RANDOM % 16]}\${ipv6_k[\$RANDOM % 16]}\${ipv6_k[\$RANDOM % 16]}\${ipv6_k[\$RANDOM % 16]}"
    }
    if [[ \$IPV6SUBNET == "64" ]]; then
    echo "\$1:\$(ipv6_ver):\$(ipv6_ver):\$(ipv6_ver):\$(ipv6_ver)"
    elif [[ \$IPV6SUBNET == "32" ]]; then
    echo "\$1:\$(ipv6_ver):\$(ipv6_ver):\$(ipv6_ver):\$(ipv6_ver):\$(ipv6_ver):\$(ipv6_ver)"
    fi
}
YENIPV6(){
echo "\${IPV6}\$(ipv6_olustur)"
}
' >> /home/proxyolusturucu/cronisleri/ipolustur$IPV6SUBNET.sh
EOF
bash ipyapici$IPV6SUBNET.sh
cat <<EOF >> /home/proxyolusturucu/cronisleri/ipdegis$yeniconfigadi.sh # This one does the main job. It changes the configuration file of 3proxy and adds IPv6 addresses to interface.
#!/bin/bash
ulimit -Hn 600000
ulimit -Hu 600000
source /home/proxyolusturucu/cronisleri/ipolustur$IPV6SUBNET.sh
yeniconfigadi="${yeniconfigadi}"
cd /home/proxyolusturucu/3proxy
rm -rf ipekle\$yeniconfigadi.sh
pidim=\$\$
tmpdosya=\$(mktemp)

while read -r ipler; do
    if [[ \$ipler == *"-e"* ]]; then
        ipler2=\$(echo "\$ipler" | grep -oP '(?<=-e)\S+')
        yeni_ipler=\$(YENIPV6 "\$ipler2")
        for ipadresleri in \$yeni_ipler; do
        echo "/usr/sbin/ip -6 addr add \$ipadresleri/$IPV6SUBNET dev $kbadi" >> ipekle\$yeniconfigadi.sh
        done
        ipler=\${ipler/"-e\$ipler2"/"-e\$yeni_ipler"}
    fi
    echo "\$ipler" >> "\$tmpdosya"
done < "\$yeniconfigadi"
mv -f "\$tmpdosya" "\$yeniconfigadi"
for pid in \$(pgrep 3proxy); do
    if [ \$pid -ne \$pidim ]; then
        kill \$pid
    fi
done
sed -i '1s/^/ulimit -Hn 600000\nulimit -Hu 600000\n/' ipekle\$yeniconfigadi.sh
sudo bash ipekle\$yeniconfigadi.sh
sudo bash ipcikar\$yeniconfigadi.sh
rm -rf ipcikar\$yeniconfigadi.sh
cp ipekle\$yeniconfigadi.sh ipcikar\$yeniconfigadi.sh
sed -i "s@addr add@addr del@g" ipcikar\$yeniconfigadi.sh
sleep 7
for configler in 3proxy.config*; do 3proxy "\$configler"; done
EOF

echo "#!/bin/bash # We are creating another bash script to run it every n seconds.
ulimit -Hn 600000
ulimit -Hu 600000
while true; do
sleep $refleshsaniye
cd /home/proxyolusturucu/cronisleri; chmod 777 ipdegis$yeniconfigadi.sh; ./ipdegis$yeniconfigadi.sh
done" >> cron$yeniconfigadi.sh
bash cron$yeniconfigadi.sh &

I tried:

Using crontab, systemd services, changing "bash cron$yeniconfigadi.sh &" with "bash cron$yeniconfigadi.sh & disown", changing "bash cron$yeniconfigadi.sh &" with "nohup bash cron$yeniconfigadi.sh &"