Freestyle: O4 and O4 Pro. While recording 4K 60fps does increase latency, not having to throw around the extra weight of a gopro makes everything more responsive. Also actions cams are not cheap.
Racing: Honestly unless you have God-tier reflexes O4/O4Pro race mode is plenty fast as it comes within 6-10ms of HDzero, just make sure you get Flywoo's wide angle camera with the O4. Otherwise just go with a cheap analog setup.