If you have the paid, premium versions of ESET and Malwarebytes, with real time protection, then you should have adequate protection against all currently known ransomware variants, although new ones are being created daily.
I back up my systems continuously on external media.
Your external backup media should only be connected to your computer long enough to back it up. Personally, I do full system images weekly, and backup changing files, in between, to USB flash drives, that are only connected to do the file copies. If your external backup drive is permanently, or semi-permanently connected, then ransomware could infect the files on that external media.
The other important security component is ensuring that your operating system has all available updates/patches, and that all vulnerable programs, like Adobe Acrobat, Flash Player, etc., are always fully updated to the latest versions.
I don't worry too much ransomware infection. If you have recent, secure backup images on external media that is not connected to your computer, and you have created Emergency Recovery bootable disk(s) for whatever backup program(s) that you are using, then the most that a new ransomware infection would do is cause you to lose an hour or so to recover a good image of your computer. Personally, I worry more about Windows Updates "borking" my computer, which has happened to me in the past, but from which I was able to successfully recover, via my backup strategy.
Hope this helps. Have a great day.