Could you please give more details on how you do this? How do you deny write access to backup location (128gb USB drive in my case) except for the backup software?It is recommended to have deny write access to sync folders except for only those programs which need access - like office productivity suite programs, video players, etc. Otherwise if your system gets smacked by ransomware and the sync folder gets encrypted, the encrypted files can be synced too and overwrite the good versions. You need to have file or backup version recovery to get out of that one.
You could just manually connect\disconnect an external backup target drive to avoid it as well. There are multiple strategies to prevent encrypted synced folders from wreaking havoc.
What I do currently is very old school, just copy/paste different folders to my USB drive (documents, music, photos are only folders on my laptop where I store my personal files), rest of SSD is only windows or installed software files, so if anything gets infected or encrypted, then I just have to reinstall Windows and my software. After my backup operation (copy paste ) I disconnect my USB drive every time.
I will try the software @BoraMurdar linked to in OP as all I care about really is the files, rest is only software I can install manually when disaster hits.
I read about free Veeam endpoint backup software too. Have not tried it yet though, but Google results say Veeam software is very good free software.