By declaring the contested territories Russian land, they can send conscripts.
That is happening.
I also suspect that by doing the above, they can then claim Russia has been invaded and use their alliances to pull other aligned nations in to the fight.
So Belarus, which has been quietly sitting by since the opening days, will be compelled to attack by their treaty.
A legal fiction, but such is diplomacy.
Xi will continue to pretend to be sympathetic while marveling at Putin's incompetence and waiting for Russia to make itself completely dependent on exporting raw materials to China and importing Chinese goods while Russia effectively becomes a Chinese colony.
I think you're onto something there, but doubt Russia will declare any new territory until locals hold a referendum to join the Russian Federation. Both the Donetsk and Lugansk republics have just announced their intentions to hold separate referenda as soon as practicable. If these succeed, I suspect Russian will use conscripts to help secure its new Russian Federation oblasts while contracted forces continue offensive operations.