Such papers aren't worth much. For example, that meta-review claims masks work. Some other scientists did a different meta-review (the A122 Cochrane Review) that concluded the opposite (strictly speaking, that there was no useful evidence masks worked). If you dig into the details of why they disagree, you'll find none of the studies claiming this stuff works are scientifically valid whilst the Cochrane meta-review is very careful. Real-world reliable evidence > models.
So what happened: activists went directly to the head of Cochrane and demanded the review be disowned, which it was, despite it having been signed off on by the org previously and there being no scientific problems identified with the study. That's how they manufacture consensus in the healthcare system: top down orders from corrupt leaders who suppress beliefs and evidence that makes them look bad. They do this because it works. After all, look at this thread. People say, look at all the evidence! Look at the consensus! They can't all be wrong!
Yet a system that concludes both yes and no simultaneously isn't worth anything. The institutions of science failed during COVID, and frankly are failing most of the time hence the replication crisis. It's not specific to masks or social distancing. We can play that game for any claim you want to make about COVID, or many other topics. Science is broken.
> explain ... evidence that standing close to someone is equal risk to standing further away from them?
There are two components to this:
1. There's a threshold value beyond which a non-immune person becomes infected and that viral load in the exposure over that doesn't matter much. Given that viruses replicate that's not surprising.
2. That a sick person can emit infectious aerosols that can hang around in the air for long periods and travel long distances e.g. via air ducts.
The intuition you're working from is that SARS-CoV-2 viruses are created in the body, that they travel only in large droplets that fall to the ground quickly due to gravity, and that risk of infection is linear in dose. Thus, being far away from an infected person should reduce the risk linearly. That's the idea the "professionals" used to justify their policies, but it's based on a model that's too far from reality to be useful. It might work for a hypothetical spherical-cow type person standing on a perfectly empty and flat 2D plane, with no air movements. It doesn't work for real world scenarios with complex layouts and complex movements of people, which is why when you look at the behavior of the virus in real settings like the Diamond Princess or jet liners the results are completely different to what the model would predict.