I think if you are careful about malware, phishing, scams, etc., Windows defender already has a top rating. Using it along with browser extensions like MalwareByte guard/uBlock origin would probably make it better.
I used Avast free and Bitdefender free before. Even if they seem to have some edge on detecting new malware and has more modules for detection, they did use more memory for me, and Bitdefender seems to have large updates making me wonder about SSD wears.
OTH, if I had a riskier profile (like have to follow questionable links, download questionable files, share a computer with less security-aware people), some products would give you an edge in detecting new malware. Free might not give you much, however, since paid products also offer more advanced malware/ransomware protections.