Definitely but offloading USD by buying out foreign USD debt with RMB is also a way to inflict damage. Let's say that freezing reserves or total sanctions is like shooting a missile or moving a tank division. It is obvious and harmful on a large scale. You do that in a war.Offload them to whom and in exchange for what?
The West has a lot of capital invested in China that would be seized in the event of theft on the scale of what happened with Russia. Furthermore, the West simply cannot function without imports from China - it's not shoes and toys, it's critical inputs to and irreplaceable components of high technology items. The West launched an economic war on Russia and shot itself in the foot, doing the same with China means shooting themselves in the head.
It's not that they're not stupid enough to do it, it's that China can do nothing to prevent or deter such stupidity and suicidal recklessness. The only thing it can do is be ready to impose its punishments when the lunatic finally snaps.
But buying out USD debt and exchanging it for RMB debt or long term contracts is a shaping operation with special forces before the war is declared. It levels the playing field by solving 2 problems simultaneously: China with too much USD and rest of the world with USD debt that forces them to use USD. Buy out their debt, and replace it with RMB debt, and both problems are solved + creates demand for RMB.