A current Windows install already has an antivirus: Microsoft Defender, real-time scanning, updates with the system. A second consumer product adds a kernel driver, its own updater, and popups. It rarely adds a verdict Defender would have missed.
Loss on your own computer usually arrives another way: a file you choose to run, a login page, a reused password, a browser extension. A resident scanner does not stand between you and Open once you have already clicked past SmartScreen.
Leave Defender on. Update the system and the browser. Do not run “activators”. Check an unknown file by hash on VirusTotal — that is a lookup, not another startup entry.
A separate antivirus makes sense on a computer used by someone who installs everything, and where policy requires it: a company, a mail gateway, EDR. That is a different machine from the laptop you maintain yourself.