Much similar to the Lokot Autonomy that appears in the game, the Belarusian Central Rada event would present the opportunity to collaborate with Belarusian partisans who opposed Soviet rule. You would get the opportunity to create unique collaboration units (much like the Lokot Autonomy event). In this event it would create the Byelorussian Auxiliary Police that would simply act as military police and increase complicity to German rule. You'd also unlock a new general (possibly ranked 2), Radasłaŭ Astroŭski, the acting political advisor of the Belarusian Central Rada.

There would however be an event much later if you chose to allow the Belarusian Central Rada, there could be a possible event later pressing for Belarusian Central Rada independence, essentially taking a small territory out of RK Ukraine and RK Ostland. You'd get a puppet status though, so it's a win essentially. However if you oppose them, it will cause unrest and possibly an insurgency.

Just an idea I had and based off of the historical establishment of the Belarusian Central Rada during World War II on 1 March 1943, and dissolved 2 July 1944 following the Soviet advance.

Enjoy!