Line 2584 in your log file:
Your bundle is locked to message_bus (2.0.5), but that version could not be
found in any of the sources listed in your Gemfile. If you haven’t changed
sources, that means the author of message_bus (2.0.5) has removed it. You’ll
need to update your bundle to a different version of message_bus (2.0.5) that
hasn’t been removed in order to install.
So you’re correct that this is caused by the RubyGem mirror you’re using.
Running the following should remove the bundler mirror config.
bundle config --delete mirror.https://rubygems.org
Here is the official doc on using mirrors with bundler.