Could you explain this a bit more mate? When you say ethnic armed forces, what are their purposes? A homeland for their ethnic group? More rights? Just generally an overthrow of the military junta? And do they all have overlapping aims?
Sorry about everything that is going on over there, hope you're staying safe.
The history and purposes of those are a bit complicated. The likes of China and even Thailand grommed them for their own interests for decades in the past.
In Shan state, there were about 8 or so armed forces. The 3 biggest keep their own territories and would fight any that step into. Those area swere well known for producing heroin and part of the infamous Golden triangle. They are so well equipped that even the military avoid having conflict with them. China probably back them as well.
But, most of others wanted to have more rights, a right to govern their own. The military has denied it since 1962. They thought it will break the union. So, they cracked down on them brutally.
Many of them have been weakened in the past decade. And, the stronger ones play politics with whoever has the central power.
Some of them lost their true purposes and went for individual interests. Most of their senior leaders are living rich in countries like Thailand or China while their foot soldiers are doing the dirty work. Their income sources are shady of course since they can't get any legitimate funds.
Failures of the previous government in the past 6 decades to do anything tangible for minority ethnic groups kept all the mess alive for as long as it has.
Now, the disposed government is trying to negotiate with all of them to unite against the military on the promises of giving them more and equal rights in a federal system.