pls don't ban me

Monthly Donor
While checking the various revolts made by Bulgarians against the ottomans i stopped on the second Tarnovo Uprising.
while composed by less man, it's main cause of failure is the premature start.
The rebellion, led by Rostislav Stratimirovic failed because only 4000 people gathered and as i stated already begun way to early in the russo-Turkish war.

So as a POD, should Rostislav manage to gather like 20 thousand people and start the revolt when the ottomans are losing is it possible for him to create a semi-independent Bulgarian state like Serbia did in the 800' ?