malwarebytes virus software

Yes, Malwarebytes is well respected and often recommended here.

You do not need the paid version. The free version doesn’t run in the background, so it doesn’t have any impact on your Mac performance (unlike the paid version). Run it only when you see unexpected behavior.

What kind of problem? Malwarebytes is about as problem free as software can be. When you download Malwarebytes, it runs as a trial version. If you decide not to purchase it, it runs as the free version which you have to run manually.

Download the free app from the developer’s site, but don’t upgrade to any of the paid options, including the Premium was trial. The app will continue to work in free mode.