Filling Tuesday afternoon: content for the quiet hours
There is an important difference between "I need more people" and "I need people when I am empty". The second case is far more common than it seems, and it is solved differently.
Why the distinction matters
If your problem is Tuesday afternoon, generic content that draws everyone in on Saturday does not help: it fills you when you were already full and leaves the rest untouched.
On top of that, an overwhelmed Saturday means worse service, and that ends up in reviews.
How to approach it
Be explicit about the slot. Let the content say when, not just what. "Tuesdays are quiet and you can take your time" is useful information, not a weakness.
Give that hour a reason. Something that only happens then: a particular preparation, unhurried attention, a product only available midweek. Without a reason, nobody changes their habits.
And set expectations: shifting people between time slots is slower than attracting new people, but it is far more profitable, because it fills capacity you are already paying for.
The same applies to the low season
Quiet months are the best time to collaborate: there is more room to look after people properly, everyone's diary is freer, and the content does not compete with the noise of the big dates.
The practical bit
Before proposing a collaboration, look at your actual week and ask yourself exactly what you want to fill. That answer should show up in the content; if it does not, you are paying for generic advertising.