Thank you for your questions.
Is a MacOS client currently being developed? (I don't want eta just if it is currently being developed)
Yes, this is what we are currently working on.
Is there anything we (as customers) can do to get the MacOS Client quicker? (As it is one of the only downsides of this software)
Is there anyway we can develop our own MacOS client?
Sorry, but there is no way for that either. We do not accept third party code and even volunteer language translations.