Russia lost most of its drone capacity when USA destroyed the Shahed factories and stockpiles in Iran and it has taken awhile for them to ramp-up their own domestic production. Both Russia and Ukraine are limited in the volume of drones operational at the same time so they deploy them as they become ready. There really isn't enough at any one time to do large coordinated swarm attacks like you're describing.

Russia had its own production of much improved versions of Shahed many months before the whole USA vs Iran shitshow.

I refuse to believe russia cannot get infinite drone supply from china

Russia has been self sufficient in drone production for more than a year. Not only that, they’ve innovated on the Shahed design by adding a jet engine. Production of drones is not the issue, lack of satellite internet is.