Duplicati 2.0.4.5_beta much slower than 2.0.3.3_beta comments on performance. If the claim of 10x performance boost is accurate (YMMV) then possibly it will more than make up for your 8-times loss.
I don’t know if your fans will run any slower. There are ways to get that, but performance will suffer…
I suspect the GUI for the Exclude section (below the Filter section) is presented by the following code:
and the fileAttributes name probably refers to FileAttributes Enum which is the OS-supported attributes, where definitions aren’t given except for Hidden, which it says macOS has. Windows also has System:
/A Displays files with specified attributes.
attributes D Directories R Read-only files
H Hidden files A Files ready for archiving
S System files I Not content indexed files
L Reparse Points O Offline files
Above is output from dir /? in a Command Prompt. Possibly you know what attributes macOS can do. Bottom line is that looking at file attributes is probably fast, up to the OS, and maybe poorly documented.
Duplicati 2.0 can include or exclude files and folders from your backup based on so-called filters. A filter can consist of various rules. And a rule decides if a file is to be included to the backup or excluded from it. This decision is made based on the name of the file or folder. Besides these name-based rules there is also a set of specific settings which exclude files with specific attributes (like system files or hidden files) or files that exceed a specific size.
Choice between ways can be nice – or confusing. If somehow the speedup in Filters isn’t enough, you could try the attributes Exclude instead, but I have an (unproven) suspicion that it won’t be as effective.