I'm an average user, and here's what I experienced:
I tried tweaking Windows Security, and experienced problems with accessing documents, etc. There were no problems with the default mode, but the system was still slow, whether in default mode or tweaked.
I switched to Kaspersky Free, and the system became more responsive. Tweaking using Optimizer also helped. It was a bit lighter than Avast Free, which comes with a firewall.
I became concerned with the limitations for the Windows built-in firewall, so I tried Comodo with Kaspersky. It worked but the system felt slower and I wasn't sure about what to do, so I removed it. (Later, I had to thoroughly remove it using uninstallers because several things still remained.)
I tried Kaspersky Standard (which has a firewall) given several trial keys shared in this forum, and the system felt a bit slower. I guess it's because when you have additional security features then there will generally be a greater system impact. The popup windows reminding me about the trial period was annoying, though, so I went back to the free version.
Given that, my advice is to use Avast free with its firewall for set-and-forget, but somewhat because you may have to set the AV in game and do-not-disturb mode to stop the unnecessary popups. The problem is that any warnings you get will appear only as a blue dot in the AV system tray icon.
If you are willing to go for paid software and want to save money, then you can probably consider Kaspersky, and Standard if you don't need the VPN, etc. You can buy a key with a discount in various stores, and when subscription is about to expire the following year, go and buy another discounted key.
There might be similar provisions in other AVs (i.e., just buy the key on promo, and see if you can enter another key bought on discount instead of paying the regular rate for the second year of subscription).
Finally, if you're a hobbyist and have lots of time to fool around with systems and find repairs for unexpected issues, then experiment away.