If you encrypt your files, none of those malware programs can "access" them - and by access, I mean open them and see what they say. But they can encrypt them again so you cannot open them without their key. So what you need to do is make sure Windows is updated and you use a good security setup (I use Windows Defender, Windows Firewall, and I do supplemental scans with Malwarebytes Antimalware), and you avoid being click-happy on unsolicited downloads, links and attachments to avoid getting infected in the first place.
You say, "i need to take a regular backup of the local files (google drive)". I am not clear what you mean by "local files (google drive)". Google Drive is "cloud" storage - that is, NOT local.
Any good, viable backup plan involves multiple backups in multiple formats and locations. So backing up to the cloud is fine, but you should also backup to something else - like an external drive. This way, if the data in the cloud storage is somehow lost, you still have the external drive.