I've stuck with Windows Defender having had issues with both Avast and Sophos home which I've tried as MS would release a Windows patch which would slow the system down because the AV was trying to scan components etc.
As for OneDrive plenty use and swear by it at work (I said swear by, not at!) as it comes part of 365 anyway.
Had to solve a few syncing issues for people which tends to be either a stored password in Credential Manager or just a case of updating the client.
