Hi @BaggersIO and welcome to the Mattermost forums!
Would it be possible to upload the logs from the desktop app somewhere so we can have a look?
@duskpunkzebra also welcome to the Mattermost forums and thanks for the detailed information.
The ~Library/Containers folder is a system folder used by all containerized applications, so it probably is hidden, but you should be able to open it after pressing Cmd + Shift + . - can you try that? This should toggle the display of hidden files and folders in Finder.