Solved Port forwarding problem

Hi all,
I promise I searched the forums first, and did about an hour and a half of work, really posting here as a last resort.
No matter what I try to do, I can't seem to open port 6112.

Testing
- I use online port checkers like www.yougetsignal.com or www.canyouseeme.org
- I test too with trying to start the game. Always the same error: need to open port 6112.
My computer settings
- I've added incoming rules in windows defender for both TCP and UDP, all network connections, for port 6112, allow incoming connections.
- I've even temporarily disabled windows firewall entirely for testing purposes.
Router settings
- I've added port forwarding for TCP and UDP 6112-6112 to my private IP.
- I've even turned on DMZ settings opening all ports temporarily for testing purposes.

I've called my ISP, asked if they've got any policy against port forwarding or if they're blocking ports. They said - no, tons of their clients use port forwarding to play games and launch servers and so forth. So, I don't think the problem is with them. The router is fairly new (6mo).
I guess I would imagine that disabling windows firewall and turning router settings to DMZ (which is insanely stupid from a security perspective, I know) would absolutely unequivocably open port 6112, even if it's just for 5 minutes and then I switch the settings back. But the game still throws the error, and the port checking websites still tell me 6112 is closed.

Any suggestions?

Thanks so much, really cool community here and hoping I can join

 

Thanks very much for your response, apologies for wasting your time with my inability to follow directions!