I've used Jamulus. During the pandemic, a friend of mine held a weekly jazz jam on Jamulus. Here's my experience. If the latency isn't extreme, your brain will automatically cause you to play your notes ahead of when you hear them, and a couple of players can actually sync with one another.
After all, this is how playing works anyway. You have to start a note before you expect it to come out of your instrument, e.g., just to be able to pull back on the string at the right time. Your brain takes care of this for you.
However, this only works if you're listening to the mix from your computer with headphones or earbuds that have good isolation. If you can hear the acoustic sound of your instrument and the sound from the mix at the same time, your brain will automatically lock to whatever comes first, and you will experience a powerful force causing the music to slow down.
For this reason, I was able to tolerate it when I was playing my electric bass with high quality headphones, but my upright bass, forget it. Likewise the people who were playing electric instruments such as keyboard did OK. Vocalists had it the worst.
It was also extremely difficult to get a bunch of musicians to understand the technical side of it, including the issue with isolation, and it just got so tiring to be the only guy holding the tempo, that it was not enjoyable. But I think a couple of people with electric instruments and a reasonable level of tech savvy should be able to do it.
We didn't try any of the other services, so I can't say how they compare.