If the first thing someone does is find a way to remove Windows Defender, I'm going to assume they're too clever for their own good. Windows defender is one of the best things Microsoft did for Windows. Prior to defender, the array of vendor AV solutions was a complete shit-show. Even previously useful options got bought out by the major players and stuffed full of crap-ware.
After being burned so many times I just stick to Defender and never had a single issue since (touch wood).