Probably the Rio de Janeiro one. The BRS Presidente Vargas corridor has a peak frequency of 600/hour, according to this site [0]. Pretty impressive IMHO.
BRTs corridors often have dedicated stations with passing/bypass lanes and dedicated pedestrian access, but in the same way that subways and light rail are just a ton of trains down the same track, pretty much.
[0]: https://brtdata.org/location/latin_america/brazil/rio_de_jan...