Windows Defender On or Off in w/ Bitdefender Free?

I'm using BitDefender Free and I think I've always had Windows Defender turned off. Had very very few issues with blocking of legit traffic/apps/websites with either. However I downloaded some Trading Software and Windows Defender blocks it. The list of exceptions is long and would be a pain in the butt to enter them all ( https://help.act.com/hc/en-us/articles/360024247434-Using-your-antivirus-firewall-software-with-Act- )

I was under the impression Windows Defender has a port blocking firewall - so people can't do things like Remote into Your Computer or utilized other network exploits that may come up in Windows. I'm just not familiar with the Bitdefender Free specifical functionality and if there are any important holes that Windows Defender fills.