Both Obsidian Sync AND Dropbox?

I want to use Obsidian Sync to sync my notes to my iPhone, and use Dropbox to sync my notes between my Windows machine and my work Mac. I am not allowed to install any other cloud sync software on my work Mac. But in the past I have experienced problems having two different sync apps working on the same folder. Has anyone tried this combination and can give feedback?
I would run Obsidian Sync on the iPhone and Windows machine, and put my vault in a Dropbox folder on my Windows machine and Mac.

Sounds like a recipe for disaster.

Here’s a vault I have in OneDrive and just turned on the core Sync plugin. Obsidian shows me this in Settings > Core plugins > Sync: