Following a chat on the issue jitsi/docker-jitsi-meet#565 for Jitsi Meet in K8S using this chart, I am moving the discussion specifically related to GKE here.

@ChrisTomAlx - could you share your findings here?

I will also provide you some support.

Is it intended to put a templated config into the prosody configmap?
and which template language is that then?
not helm template is it?
it does not have tobool

Also I do find the base64 encoded files and some uncommented code

lifecycle:

      #   postStart:
      #     exec:
      #       command:
      #         - /bin/bash
      #         - -c
      #         - cat /var/app/prosody.cfg.lua | base64 -d > /defaults/prosody.cfg.lua
      #         - cat /var/app/jitsi-meet.cfg.lua | base64 -d > /defaults/conf.d/jitsi-meet.cfg.lua
      #         # {{ if .Values.prosody.auth.enabled }}
      #         # - prosodyctl --config /config/prosody.cfg.lua register me $XMPP_DOMAIN $JVB_AUTH_PASSWORD;
      #         # {{ end }}

Did this ever work? If not please add a comment.
Its so deeply in the logic that its simply not fair to leave this uncommented for others to run against a wall.
Thats the beauti of READMEs.