Add .dropboxignore directory to exclude folders without using selective sync

The following idea have already been suggested in the post below :

https://www.dropboxforum.com/t5/Dropbox-ideas/Ignore-folder-without-selective-sync/idi-p/5926

However, it hasn't been implemented because the author suggested other solutions that doesn't solve my problem.

TL;DR : I would like to have a list of pattern that dropbox sync will ignore, no matter what.

Context : I like the idea of having my file backed up without even thinking about it using dropbox. However, during my work, I frequently create, edit and/or delete files/folders during automatic procedures and dropbox oftenly make these procedures fail by opening these files/folder in blocking mode.

Idea : Mimic the .gitignore method to add a list of pattern to exclude from sync anytime, so files/folders that are dynamically created doesn't get busy from dropbox sync procedure and some dropbox server & storage load could be saved this way (it's a win-win situation).

I'm aware dropbox already implement a static ignore list using selective sync or rightclick -> online, but  1. this doesn't solve the issue for dynamically generated files/folders ; 2. this is way to much a hassle when you have a lot of them/ add a new one ; 3. At my current knowledge, this doesn't work for files.