[Dropbox] Add a feature to mount Dropbox as a drive

Hello! I would appreciate any suggestions folks may have for my predicament. I am trying to backup my Dropbox folder that uses a combination of local, online, and selective sync to an external drive. I pay for the Dropbox Plus plan and essentially use my Dropbox as a home folder for most of my working files. I am currently using just under 1 TB of the 2 TB of storage I have available to me. I have a 1 TB SSD with ~300 GB remaining on my laptop and in order to preserve space I use a combination of storing the files locally for offline use, storing some files as online only if they're infrequently accessed, and using selective sync to effectively 'hide' folders that are not accessed frequently. I have been using Backblaze Personal as a backup in the event my Dropbox folder gets deleted. However, I recently learned that Backblaze has stopped backing up cloud folders like Dropbox/Google Drive/iCloud/OneDrive, which has me looking into backing up my entire Dropbox folder to an external drive. Is there an easy way to do this given the mixture of local/online/selective sync for my Dropbox? I can't just store all the files locally because I don't have enough internal SSD space. I've heard that trying to download large zip files from Dropbox can often lead to errors. I was thinking it could be great if I could mount the Dropbox folder as a drive on my computer, and use FreeFileSync to back it up to an external drive. Unfortunately, I've read a couple of horror stories about CloudMounter. It seems like perhaps rclone is a relevant tool, but I am not comfortable in Terminal and would be a little worried about messing something up. I appreciate any suggestions/thoughts folks might have. Thanks for your help!