This is a list of jitsi instances that may work better than then Jitsi official public instance which may be too busy sometimes. if there are too many people using at the same time then it may be slow.
list of alternative jitsi instances
komuniki
list of community run instances
libre service by libre_service.eu
the concept of “instances”
jitsi is an open source free tool. the code is available. anybody can copy the code and install it on their own server / cloud. as you can see above, there are many organizations that offer their instance for free to the public to use.