I recently did a fresh install of Windows 10 AU. So far, 3 weeks, I've only been using Windows Defender and haven't install Kaspersky. And I definitely can tell my computer performs better without Kaspersky installed. I know you weren't asking this but just thought I'd give my 2 cents about that.
I haven't heard if MS is going to put in the ability to completely turn off Defender. I mean, most people on this forum have their main AV, then at least 1 or 2 other malware scanners installed along side their AV. Can you can increase your RAM so your games don't experience that hit when Defender is running/scanning?