I tested a few games with my netduma router, 17 out of 20 games on US servers. Check this google sheet:
Playing SWAT with 150 ms latency isn’t fun. With the region lock most games went flawless. Sometimes I couldn’t find games at 3am, but is was worth the perfect experience. Close games and amazing hit detection. Now I am dying around corners, enemies eating bullets, I get shot out of nowhere, people teleport over the map.
I do not know how a solution should look like . With region lock some people can not find any matches . Without Region Lock it lags and it is no fun.