I can't speak for FaceTime, but I've found much better success with all of these platforms if everyone in the meeting is wearing headphones. A lot of the latency is from echo cancellation, and that turns off if there's no echo.
At my last company, I let everyone on my team expense comfortable headphones with a boom mic, and it made a huge difference on Google Meet. I've found Zoom to be similar. I can't speak to Slack's latency issues.
I'm also a big fan of Tuple[0] (the pair coding app) for extremely low latency screen sharing / pair coding and that was a huge advantage too.
At my last company, I let everyone on my team expense comfortable headphones with a boom mic, and it made a huge difference on Google Meet. I've found Zoom to be similar. I can't speak to Slack's latency issues.
I'm also a big fan of Tuple[0] (the pair coding app) for extremely low latency screen sharing / pair coding and that was a huge advantage too.
[0] https://www.tuple.app