for a
TN in accounting, you must have EITHER baccalaureate, CPA, CA, CGA, or CMA.
So, given that you will not have a bach degree in accounting, you must therefore get one of the other designations, by qualifying BEFORE trying to get a tN.
So it is not really a catch-22, it means you must first get your designation in Canada, then you can get your TN.
That is by design. It matches up with other TN categories which require degree OR (diploma + experience).