I have a friend who uses two workstations, one is a Fedora Workstation and the second is a Fedora SIlverblue, both version 38.
I use Ubuntu the latest LTS. We tried Jami (Flatpak) on his main station (Workstation 38) and on mine Ubuntu (Snap Store). After a few minutes it crashed for him a few times and for me it crashed twice.
We find such program very useful for teaching people in needs, e.g. in NGOs.
Could you provide a log?
Where is the log?
We tried again Jami. Chatting and sending files it works fine. Even we sent to each other a file (5.5 MB) and second PDF at the same time. Perfect!
But again with voice only, it crashed on both computers.
Flatpak version is strange. I passed -d argument to jami but can’t get debug messages. 
flatpak run --file-forwarding net.jami.Jami -d
Did you try starting jami from a terminal? Can you get any information when it crashed?