This is my experience with Jamulus, too. However, to get down to 10-40ms, you need to setup your tech as follows.

- ethernet instead of wlan

- dedicated audio interface, takes calculation overhead off your computer

- a proper microphone, improves acoustics greatly

All of these steps will increase Zoom/Skype experience, too. However, Zoom/Skype will hardly go below 100s of ms of latency, just by themselves.