Sometimes very effective, sometimes not
Low, localised sources such as a patio, pool area or dog run can be suitable for targeted shielding. Sound from upper-floor windows or many different directions is much harder.
Protect the place that matters
You may not need to shield the entire boundary. A local barrier around one seating area can sometimes be the smarter solution.
The useful question is not “Can I make my neighbours silent?” but “Can I make my own outdoor space meaningfully calmer?”
The automated Reality Check is not designed for neighbour noise. This is a better fit for a personal assessment.