I also use Windows built-in Defender. Free and top rated by independent security orgs. MS is well vested in security infrastructure that other app manufactures rely for threat info. Personally, haven't paid for AV software in over 20 years.
You don't necessarily get better protection by paying for AV software. Plus its only one aspect of overall security. Keeping your OS, browsers, and software updated with security patches is more important than ever. Plus knowledge of common hacker tactics such as social engineering adds another layer of protection.
Also, if you do the research, you'll find that some of the highly rated paid AV software have been exploited by hackers in the past. Some multiple times. This is particularly dangerous for AV software as it requires elevated privileges on you system to even work. Which gives a successful hacker pretty much free rein to do what they want on your system.