Thank you for asking the question.
There are very serious implications. It comes down to the question of the organizations that control, with de facto powers, the territory that borders the country. This has implications for the situation of the Rohingya. It has implications for the wider country's situation of conflict, and it also has implications for Bangladesh.
It's not clear exactly what the Arakan Army will do with that border, but it is clear that any action done within Rakhine state needs to be done with the actors on the ground. That means international organizations may need to work with the Arakan Army and may need to work with Rohingya groups to provide humanitarian assistance effectively. There are various ways to do that, and there's the tool of using condemnation, especially if these groups are enacting atrocities towards the Rohingya.
For the second question on cross-border analysis, essentially, analyzing Myanmar in the context of who controls the borders is very important for understanding the situation. You can't really understand humanitarian assistance as a whole within Myanmar without considering that many of these ethnic revolutionary organizations, resistance organizations, control most of Myanmar's border. They are responsible for humanitarian assistance. They are responsible for the security situation on the ground. You can't expect the junta, which doesn't have control of these areas, to provide humanitarian assistance without control of those areas. Working with these border organizations, the ethnic revolutionary organizations, would allow more assistance to be provided.