Jitsi vs Zoom

yesterday I started a test with about 10 Users.
We tried first Jitsi and then Zoom. Both with the smartphone Apps.
Result for audio/video quality and overall stability: Jitsi reached in our option about 80-85%. Zoom 95% (there are almost no problems)
Additional I measured the up/download of my internet connection and I realized that Zoom only use the half of the Jitsi traffic.

Can anybody say, what the problem is?
Can I do anything to make Jitsi as good as Zoom is?