I've been looking for a combination that worked and for the first time I played with this pair yesterday:
Transmitter: Trond aptX Low Latency
In-ears: MEE Audio M6 Pro (2nd Gen)
I was playing bass and really only had vocals in the ears but I experienced no latency issues. It might be different playing keys or guitar with these as the only monitors - I haven't tried that yet. When I experimented at home before the gig there was a perceptible delay but it was very small and it didn't bother me live. Either that or I was just late...