In my experience antivirus software is not worth the cost of system resources. AV that tries to actively mitigate threats can really bog down your system.

Definitely purge McAfee as soon as possible.

Like the others have said, as long as you don't frequent sketchy websites, you will be just fine with Windows Defender.

Also, if your Windows Defender ever detects something you may want to run an additional scan with Malwarebytes just to cover your bases.