Ukraine somehow coped with the task of mobilizing more than 800k civilians, Russia has a simpler task.
Sending thousands of untrained drunks armed with rusty kalashnikovs against HIMARS is indeed quite simple. Not very effective though.
We'll see. So far, it looks more like Russia is increasing its military grouping in Ukraine by at least 2.5 times, due to the mobilization of reservists with military service experience.