I can not confg DMZ I access SQL server by 5g sim card with huawei router

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I have a new server Dell 740 gold and it running by 5g router Huawei Model: H112-370
I try everything i have and it still the public IP can not see in the external network (remote desktop & SQL Server IP & DDNS ...etc) I failed to access from outside the network and I am sure I miss something and I am sure it's not from our provider the don't close any port I here in KSA (Saudi Arabia) the sim card from STC Company
and solution by VPN or any third-party or direct solution I really have two days to try to solve this problem

What I have tried:

i config in route and set DMZ for static local server IP and it not work
I open the port 1433 and 1434 and 3389 and I turn off the firewall both in the router and in dell server to be sure its blocked for security reasons and it still does not work the external IP.
i use nordVPN for Dedicated IP to solve the problem and its not working for me

I need help and its the first equation here from many years I use

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