I want to open a port so others can connect to me and we can form a server
I used UPNP on my TP router but the port still shows as closed for me.
Others cannot connect to me either.

I tried creating a virtual server using TP router interface, entering the same port number for TDP and UDP, still closed.
I made sure to use my local ip address for the computer as the internal address.
Not sure what is going on.

I don't have a firewall, just use windows defender with malwarebyte.

You may need to configure the router to forward inbound connections to a local IP address.

ShieldsUp! is a great method for remotely testing which ports are 'open', 'closed', or, purposefully non-responsive.

After visiting the initial page, just under 'You may select any service from among those listed above . . .', there is a field to input a given TCP port number. After doing so, you may simply select 'User Specified Custom Port Probe'.

This is quite useful when altering router settings (and, for whichever reason, a trusted third party familiar with Nmap is unavailable).

If you would prefer, we may thoroughly explore this topic through private message. : )

What about Windows' built-in firewall? Is it active?

Win 7: Settings > Windows Firewall
Win 10: Settings > Update & Security > Windows Security > Firewall & network protection
Win 11: Settings > Privacy & Security > Windows Security > Firewall & network protection

Haven't done this yet. Will give this a try.
Edit: Checkmark next to the app name = allowed?

I have the checkmark on the left to the app checked
and both checkmarks under public and private categories on the right checked.

Have you also taken a look at https://portforward.com/router.htm ?