In my opinion, of course there's no such thing as the best antivirus, but there is the "best antivirus for your specific needs", like @I Walk MY Way mentioned.
Choosing the perfect antivirus for yourself should be the answer to many previous questions, as for example:
What type of user am I? Am I an advanced user or am I a security novice?
Of course when you're a novice in security you'll need a bit of extra help. Not knowing your security ABCs will constantly put you in risk and no antivirus will be enough to protect you from yourself, but some will provide better defense than others. You can achieve a certain lockdown in your system with specific security suites, if you tweak them enough; while there are others that will just protect you in automatic mode, without the need of you doing anything.
Am I willing to pay for an antivirus?
This is another important factor. Usually, more advanced suites require a payment or subscription. If you are a novice user and can't afford to pay for security, you'd probably be better off learning and studying about cybersecurity, in order to be able to understand and use complements for a free antivirus (like Hard_Configurator, ConfigureDefender, etc).
What type of use do I give my PC?
In matter of security, it's not the same if you use your computer for Netflix and Youtube, than if you use it for gaming, torrenting and browsing. The more attack vectors you add, the most complex solution you need. Most advanced users (those who know how to surf, block ads, don't crack software) would be okay with Microsoft Defender alone. But if you are a risky user who likes to do shady things, you will most certainly need better protection.
These are only a few questions you can ask yourself to know wether you need basic or solid protection.
But of course there are some things you SHOULDN'T do as well, as for example:
Don't rely on AV-Testing like AV-TESTS, AV-COMPARATIVES, PC-MAG, etc. Despite some of them may actually be, let's say, "accurate" they do not represent your system or how malware and antivirus software would behave on your specific system. For this, trust your own tests or MalwareTips testers, whose virtual environment is much more similar to yours.
Do not rely as well 100% on a single test: two days and two malware packs are not enough to conclude Kaspersky is the best against ransomware malware. If you're not willing to make your own tests, research for many tests that could actually represent your system. Make sure fresh packs are used and system configuration is settled as you would use it.
Do not use more than two antivirus or same software: OK, most users know that. Still many new members have no clue on what i'm talking about. Two or more antivirus suites or software with the same purpose, say two firewalls, will NOT give you more security layers. On the other hand, this will conclude on excessive CPU and RAM usage, BSOD, incompatibility and less security, since they will end up disabling components and highlighting as possible malware.