You are very right to work this feature as a global restriction instead of doing it field by field.
Is there any chance this new feature could also help filtering the inline-filters shown to the end user when the shown filters are coming from linked records?
This is great news! Although we would much prefer the mockup solution by @PaulKalvelage (or even a combination of global and local), this could be incredibly useful. We have spent countless hours trying to find workarounds only to hit a dead end time and time again.
We will support both eventually 
Right now we’re exploring 1) global restrictions based on user’s record ownership → This extends to not just dropdown but also inline filter, conditional filter on each block. It’s the most critical for any portal use cases.
Something similar @PaulKalvelage’s solution will also be needed → This 2) local filter can filter data based on other variables, such as:
I have at least two big projects that are blocked by this limit. An implementation like this could lead to a “boom” in the use of Softr in numerous contexts! We are waiting! 
