When will the full Collaborative Calling functionality be available? When asking MS support about the missing call history in Teams channels they stated:
Shared call history for agents in Voice Enabled Channels is not yet implemented.
You'll see your individual agent call queue history and previews of your call queue's shared transcribed voicemail.
Call queue calls are not logged. There is no call history even when the call has been answered by a member of the call queue. (Call history in channel will only show calls answered by the Teams user/agent's own call history)

This blog post from 3 years ago shows screen grabs from Ignite 2020 showing call history, call back options, etc... https://techcommunity.microsoft.com/t5/microsoft-teams-blog/what-s-new-in-microsoft-teams-microsoft-ignite-2020/ba-p/1665600#calling