themrpotato try to add the same port in internal port too in your rule
Also for this to work you need to open the bat, it's not made for private games, it's a server.
And last thing you need to let the server open for like 30s until there's a heartbeat for it to be joinable, it's not instant
If you're sure you only have Windows Defender then add a firewall rule for both incoming and outgoing connections. Also.maybe check both public and private for plutonium-bootstrapper32.exe
And the most important are you 100% sure the local IPv4 on your port forward rule is the local IPv4 of your PC right now? It could've changed. Open a cmd in Windows and type ipconfig to see