In all seriousness, nice set up. If you can overclock the Ryzen beyond 3.4 you'll be laughing.
I didn't bother with antivirus for a long time and relied on Windows Defender. But then I've never used my gaming PC for accessing porn .
I have recently installed Avast, the free version. Some will tell you these antivirus applications are as bad as having malware, but I'm no expert.
I stopped using Ccleaner because two of my drives are SSD, only one is HDD. As far as I can tell, Windows 10 is pretty good at cleaning up after itself but others on the forum with more know-how will probably guide you better...