I cannot change my NAT type

Hello everyone, so I'm having an issue here, I cannot for the life of me change my NAT type, I've tried pretty much everything and I'm at my limit and at the end of my resources, here's what I have tried so far:

- Changing my modem settings, and my signal repeater settings to have UPnP on

- Port forwarding for specific games like GTA V

- Turning on DMZ

- Calling my ISP, they say NAT is open on their side

- Got a new modem from my ISP

- Changed settings in Windows Defender Firewall

- Turned off Windows Defender Firewall

And after all of this, my NAT is still Symetric. I am feeling tired, defeated and just at my limits, please can someone help me?