I really don’t care about the cost. I care about securing my user accounts. I will not succumb to a cloud-based OS like Microsoft 365. You may like it, maybe even love it, but I don’t. I would switch to whatever OS platform that allows me local control.
Since Windows 10, what’s built-in (Windows Defender) is more than secure enough for home users. Most third-party security apps, including the free ones, are safe but worse than useless because all they do is slow your system down significantly. I’m not trying to change your mind, just making sure that other FR members get more than one side of the story.
If you really want to secure accounts you can set up a Windows domain controller on a linux server. Both are “free”- except for few days of your time. I’ve never bothered, and most enterprise customers pay for Windows Server because it’s cheaper than paying someone full-time for “free” linux anything.