This is a hard one... the parent commenter mentioned that there should be some indication about when people were told to wear masks in the charts that show the spread of the virus in at least some countries. That's difficult to see anywhere... the study you link to says that they were simply unable to show whether masks are effective because of "the high risk of bias in the trials, variation in outcome measurement, and relatively low adherence with the interventions during the studies".
Let me give a little anecdote about that... Brazil was one of the worst affected countries, despite having made it mandatory to wear masks. Sweden, on the other hand, only made it mandatory to wear masks in a few very limited situations (e.g. public transport), and even then, only after the pandemic was already dying down, much later than most countries. And Sweden seems to have had a below OECD average rate of deaths due to the pandemic.
I know it's a difficult comparison to make: Sweden's healthcare system is likely more "competent" than Brazil's (because it can afford much more, but both have free or nearly free healthcare available to everyone) and people in Sweden tended to be less skeptical of the virus (personal experience, not sure this can be shown by data) - that makes a big difference as people in Brazil would often wear a mask just because they were forced to, and hence wore it incorrectly and didn't really try hard to make it effective, while in Sweden people did it by their own accord (for the longest time, Sweden only recommended to wear, but did not make the mask mandatory) and were much more likely to have done their research about how to better make use of the mask to avoid getting infected.
Also, it has been shown that most deaths in Sweden occurred early on, among the elderly living in nursing homes where employees (who are almost always foreigners with a very different culture and hence, I suggest, less likely to properly wear masks and follow government recommendations to contain the spread of the virus, like completely avoiding meeting people who are not living in the same household) were the main source of infections - so if you take that into account, the fact that people in Sweden were mostly not wearing masks at all for most of the pandemic should show that, at the very least, wearing masks was not the most effective way to keep the virus under control.
My takeaway is that masks may help, but only if you actually believe it will help and take sufficient care to wear a proper mask and do it properly... and that other measures, like voluntary social distancing, turned out to have been more effective than just wearing masks.
Let me give a little anecdote about that... Brazil was one of the worst affected countries, despite having made it mandatory to wear masks. Sweden, on the other hand, only made it mandatory to wear masks in a few very limited situations (e.g. public transport), and even then, only after the pandemic was already dying down, much later than most countries. And Sweden seems to have had a below OECD average rate of deaths due to the pandemic.
I know it's a difficult comparison to make: Sweden's healthcare system is likely more "competent" than Brazil's (because it can afford much more, but both have free or nearly free healthcare available to everyone) and people in Sweden tended to be less skeptical of the virus (personal experience, not sure this can be shown by data) - that makes a big difference as people in Brazil would often wear a mask just because they were forced to, and hence wore it incorrectly and didn't really try hard to make it effective, while in Sweden people did it by their own accord (for the longest time, Sweden only recommended to wear, but did not make the mask mandatory) and were much more likely to have done their research about how to better make use of the mask to avoid getting infected.
Also, it has been shown that most deaths in Sweden occurred early on, among the elderly living in nursing homes where employees (who are almost always foreigners with a very different culture and hence, I suggest, less likely to properly wear masks and follow government recommendations to contain the spread of the virus, like completely avoiding meeting people who are not living in the same household) were the main source of infections - so if you take that into account, the fact that people in Sweden were mostly not wearing masks at all for most of the pandemic should show that, at the very least, wearing masks was not the most effective way to keep the virus under control.
My takeaway is that masks may help, but only if you actually believe it will help and take sufficient care to wear a proper mask and do it properly... and that other measures, like voluntary social distancing, turned out to have been more effective than just wearing masks.