An integrated threat protection solution designed to detect, investigate, and respond to cyber threats across Microsoft 365 services.
You should never install multiple antiviruses on a PC.
Defender is fine as an antivirus (no need for anything else on that front), but it doesn't protect again adware, malware, ... So you should look into anti-malware protection. Perhaps simply use the free version of Malwarebytes and do manual scans like once a week, but there are tons more on the market.
I also like things like SpywareBlaster to harden your browsers.
Lastly, your best line of defense will always be a good backup plan so should the worse ever happen you are in a position to quickly and easily recover your data!!!
As a side note, based on my experiences I recommend staying away from Norton, Avast, AVG....
As a second side note, you've posted your question in a Microsoft Access database forum. To get the help you seek you should repost it in a more appropriate forum.