So just to let others know, the solution to the issue was to modify the default callback for the python version being used.
%ansible python module location%/plugins/callback/default.py
%ansible python module location% = the python path ansible is using (ansible --version)
By commenting out the “v2_runner_on_async_poll/ok/failed” block sections I managed to remove the (IMO useless) async messages.
The DIY callback currently doesn’t include these async runners and as such does not show these messages, however the DIY callback also doesn’t currently support pretty formatting.
Hence this is why I modified the default callback instead since it was a simple solution and I am not ready to write my own callback just to remove those async messages.
Anyway, hopefully this helps others looking to remove these async messages as well.