I’ve been following it for a few weeks, it was a snowball effect.
The original protest was met with mockery and ignorance where Hasina called the protestors “rajakars”, which refers to the people who aided Pakistan during the genocide in the 70s. That caused even bigger protests.
The government’s youth wing/league, likened to a gang or terrorist group, violently beat protestors and killed some. In the chaos, police fired on protestors, drove cars through rickshaws, and started showing up to homes in plainclothes at night arresting students. More happened but this is what I saw videos of. Many more were killed during this time. To slow the spread of news about this, the government shut down the internet. At this point the people wanted her out of power.
Further growing protests were met with more violence, a curfew, and a shoot on sight order. The youth wing attacked people on the street and police fired at people outside. People were shot at even when standing by the windows or on the rooftops.
All of thus culminated in people flooding to the capital, filling the city centres and Hasina fleeing the country.
While its very likely that opposition party members supported the protests, too much happened for it to be entirely manufactured.