Haha yeah, I promise it's clean (infrastructure engineer here).
This is a common occurrence with Unity (my guess is it has something to do with all the telemetry they collect now for advertising and what not), a quick google will show this. I run Malwarebytes on everything I upload along with virus checker, which I have linked above.
As for the game being flagged, I'm going to see if there's something I can disable so this doesn't happen in future builds.
Edit: I've done some digging and I can go about signing the builds but that requires a LOT of money to set up. I'll tinker with some distribution options and see if maybe it's the file being in a zip that does it. Either way, this is very high on my priority list to fix.