You are talking about the exception rather than the rule (for the NRL).
Less than a few % of players have made it to NRL level being shorter than 5'9 or so.
You are definitely talking about the exception rather than the rule for the NRL. For football, you can definitely be short and it can be on occasions be beneficial.
The debate is only central to the real top athletic talent. There are only the very few who have the athletic makeup to be a top line player in say both basketball, NRL and soccer etc. You would be over 6’5, quick and powerful. If you are over 7ft for example, you are likely to be too slow to play football or NRL