The way you frame the situation is hardly justified, most of what you say doesn't match any of the commonly accepted explanations.
First of all, it's not bad president against good protestors. There were actually two things going on on the streets: peaceful protestors with political and economical demands, and armed organized bandits/terrorists wreaking havoc and destabilising situation as much as they could.
The bandits were killing the police (also going to hospitals to finish any wounded police officers they could find), storming jails trying to set criminals free, burning government buildings, they gave fake calls to firefighters and killed the crews when those arrived.
I leave it to you to read up on who could be orchestrating the bandits. I suggest you focus on local (CIS-based, Russian speaking) news media and telegram channels for that. But one of the important hypotheses is that it was all made by the forces in power opposing Tokaev (the president), and he called the Russians because he didn't trust his own men's loyalty. Russians were protecting some critical infrastructure (which never got attacked, so they didn't fight anyone) including president's headquarters (which was very, very far from the core of riots).