I used Malwarebytes in past, but now I’m not using any antivirus on my Mac. Since my main development machine is one with Ubuntu which also have Windows 10 which I occasionally need, and I use Mac sparingly, and install only XCode, Visual Studio Code and couple of more tools, so I think it’s safe to use it without an antivirus.
Currently I’m using a late 2013 MacBook pro, and may buy a new MacBook Pro if Apple releases a 16 inch one with Apple silicon (M1/M2/Mx). That may become my main development machine and in that case I’ll be using an antivirus on it.

I don’t use any antivirus, partly because I didn’t even know there was one!

I’m usually really skeptical about antiviruses because they’re usually the virus—unwanted ads and computer slowdowns

Nope. I’m not taking unnecessary risks in general but have also made peace with the fact that installing one of the million possible dev tools is a constant risk that I can’t mitigate.