Personally I've not used a third party virus / system manager since the days of XP I put my trust in my router and windows firewall. Windows Defender has never indicated an infection in the last 12 years of win 7 and win 10
I am in the fortunate position that my simulator pc is only used for flight sim. Its not used for email, browsing or any downloads, and is only connected to the Web for FSA client and I suppose Windows updates. I use another pc for downloading which I then upload to my NAS drive, before transferring to the simulator. All my "late night" browsing or any other time for that matter, is done with an android tablet As far as I know any infection to the tablet (not that I've ever had one) can't be transfered to a pc on the network, they are not switched on anyway, although I stand to be corrected
Dale